Archives
/
jamiebuilds_the-super-tiny-compiler
mirror of https://github.com/jamiebuilds/the-super-tiny-compiler
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Init commit

Browse Source
pull/30/merge
James Kyle 8 years ago
commit 3356bea996
4 changed files with 1460 additions and 0 deletions
Show Stats Download Patch File Download Diff File

393
LICENSE
Unescape View File

@ -0,0 +1,393 @@
Creative Commons Attribution 4.0 International
=======================================================================
Creative Commons Corporation ("Creative Commons") is not a law firm and
does not provide legal services or legal advice. Distribution of
Creative Commons public licenses does not create a lawyer-client or
other relationship. Creative Commons makes its licenses and related
information available on an "as-is" basis. Creative Commons gives no
warranties regarding its licenses, any material licensed under their
terms and conditions, or any related information. Creative Commons
disclaims all liability for damages resulting from their use to the
fullest extent possible.
Using Creative Commons Public Licenses
Creative Commons public licenses provide a standard set of terms and
conditions that creators and other rights holders may use to share
original works of authorship and other material subject to copyright
and certain other rights specified in the public license below. The
following considerations are for informational purposes only, are not
exhaustive, and do not form part of our licenses.
Considerations for licensors: Our public licenses are
intended for use by those authorized to give the public
permission to use material in ways otherwise restricted by
copyright and certain other rights. Our licenses are
irrevocable. Licensors should read and understand the terms
and conditions of the license they choose before applying it.
Licensors should also secure all rights necessary before
applying our licenses so that the public can reuse the
material as expected. Licensors should clearly mark any
material not subject to the license. This includes other CC-
licensed material, or material used under an exception or
limitation to copyright. More considerations for licensors:
wiki.creativecommons.org/Considerations_for_licensors
Considerations for the public: By using one of our public
licenses, a licensor grants the public permission to use the
licensed material under specified terms and conditions. If
the licensor's permission is not necessary for any reason--for
example, because of any applicable exception or limitation to
copyright--then that use is not regulated by the license. Our
licenses grant only permissions under copyright and certain
other rights that a licensor has authority to grant. Use of
the licensed material may still be restricted for other
reasons, including because others have copyright or other
rights in the material. A licensor may make special requests,
such as asking that all changes be marked or described.
Although not required by our licenses, you are encouraged to
respect those requests where reasonable. More_considerations
for the public:
wiki.creativecommons.org/Considerations_for_licensees
=======================================================================
Creative Commons Attribution 4.0 International Public License
By exercising the Licensed Rights (defined below), You accept and agree
to be bound by the terms and conditions of this Creative Commons
Attribution 4.0 International Public License ("Public License"). To the
extent this Public License may be interpreted as a contract, You are
granted the Licensed Rights in consideration of Your acceptance of
these terms and conditions, and the Licensor grants You such rights in
consideration of benefits the Licensor receives from making the
Licensed Material available under these terms and conditions.
Section 1 -- Definitions.
a. Adapted Material means material subject to Copyright and Similar
Rights that is derived from or based upon the Licensed Material
and in which the Licensed Material is translated, altered,
arranged, transformed, or otherwise modified in a manner requiring
permission under the Copyright and Similar Rights held by the
Licensor. For purposes of this Public License, where the Licensed
Material is a musical work, performance, or sound recording,
Adapted Material is always produced where the Licensed Material is
synched in timed relation with a moving image.
b. Adapter's License means the license You apply to Your Copyright
and Similar Rights in Your contributions to Adapted Material in
accordance with the terms and conditions of this Public License.
c. Copyright and Similar Rights means copyright and/or similar rights
closely related to copyright including, without limitation,
performance, broadcast, sound recording, and Sui Generis Database
Rights, without regard to how the rights are labeled or
categorized. For purposes of this Public License, the rights
specified in Section 2(b)(1)-(2) are not Copyright and Similar
Rights.
d. Effective Technological Measures means those measures that, in the
absence of proper authority, may not be circumvented under laws
fulfilling obligations under Article 11 of the WIPO Copyright
Treaty adopted on December 20, 1996, and/or similar international
agreements.
e. Exceptions and Limitations means fair use, fair dealing, and/or
any other exception or limitation to Copyright and Similar Rights
that applies to Your use of the Licensed Material.
f. Licensed Material means the artistic or literary work, database,
or other material to which the Licensor applied this Public
License.
g. Licensed Rights means the rights granted to You subject to the
terms and conditions of this Public License, which are limited to
all Copyright and Similar Rights that apply to Your use of the
Licensed Material and that the Licensor has authority to license.
h. Licensor means the individual(s) or entity(ies) granting rights
under this Public License.
i. Share means to provide material to the public by any means or
process that requires permission under the Licensed Rights, such
as reproduction, public display, public performance, distribution,
dissemination, communication, or importation, and to make material
available to the public including in ways that members of the
public may access the material from a place and at a time
individually chosen by them.
j. Sui Generis Database Rights means rights other than copyright
resulting from Directive 96/9/EC of the European Parliament and of
the Council of 11 March 1996 on the legal protection of databases,
as amended and/or succeeded, as well as other essentially
equivalent rights anywhere in the world.
k. You means the individual or entity exercising the Licensed Rights
under this Public License. Your has a corresponding meaning.
Section 2 -- Scope.
a. License grant.
1. Subject to the terms and conditions of this Public License,
the Licensor hereby grants You a worldwide, royalty-free,
non-sublicensable, non-exclusive, irrevocable license to
exercise the Licensed Rights in the Licensed Material to:
a. reproduce and Share the Licensed Material, in whole or
in part; and
b. produce, reproduce, and Share Adapted Material.
2. Exceptions and Limitations. For the avoidance of doubt, where
Exceptions and Limitations apply to Your use, this Public
License does not apply, and You do not need to comply with
its terms and conditions.
3. Term. The term of this Public License is specified in Section
6(a).
4. Media and formats; technical modifications allowed. The
Licensor authorizes You to exercise the Licensed Rights in
all media and formats whether now known or hereafter created,
and to make technical modifications necessary to do so. The
Licensor waives and/or agrees not to assert any right or
authority to forbid You from making technical modifications
necessary to exercise the Licensed Rights, including
technical modifications necessary to circumvent Effective
Technological Measures. For purposes of this Public License,
simply making modifications authorized by this Section 2(a)
(4) never produces Adapted Material.
5. Downstream recipients.
a. Offer from the Licensor -- Licensed Material. Every
recipient of the Licensed Material automatically
receives an offer from the Licensor to exercise the
Licensed Rights under the terms and conditions of this
Public License.
b. No downstream restrictions. You may not offer or impose
any additional or different terms or conditions on, or
apply any Effective Technological Measures to, the
Licensed Material if doing so restricts exercise of the
Licensed Rights by any recipient of the Licensed
Material.
6. No endorsement. Nothing in this Public License constitutes or
may be construed as permission to assert or imply that You
are, or that Your use of the Licensed Material is, connected
with, or sponsored, endorsed, or granted official status by,
the Licensor or others designated to receive attribution as
provided in Section 3(a)(1)(A)(i).
b. Other rights.
1. Moral rights, such as the right of integrity, are not
licensed under this Public License, nor are publicity,
privacy, and/or other similar personality rights; however, to
the extent possible, the Licensor waives and/or agrees not to
assert any such rights held by the Licensor to the limited
extent necessary to allow You to exercise the Licensed
Rights, but not otherwise.
2. Patent and trademark rights are not licensed under this
Public License.
3. To the extent possible, the Licensor waives any right to
collect royalties from You for the exercise of the Licensed
Rights, whether directly or through a collecting society
under any voluntary or waivable statutory or compulsory
licensing scheme. In all other cases the Licensor expressly
reserves any right to collect such royalties.
Section 3 -- License Conditions.
Your exercise of the Licensed Rights is expressly made subject to the
following conditions.
a. Attribution.
1. If You Share the Licensed Material (including in modified
form), You must:
a. retain the following if it is supplied by the Licensor
with the Licensed Material:
i. identification of the creator(s) of the Licensed
Material and any others designated to receive
attribution, in any reasonable manner requested by
the Licensor (including by pseudonym if
designated);
ii. a copyright notice;
iii. a notice that refers to this Public License;
iv. a notice that refers to the disclaimer of
warranties;
v. a URI or hyperlink to the Licensed Material to the
extent reasonably practicable;
b. indicate if You modified the Licensed Material and
retain an indication of any previous modifications; and
c. indicate the Licensed Material is licensed under this
Public License, and include the text of, or the URI or
hyperlink to, this Public License.
2. You may satisfy the conditions in Section 3(a)(1) in any
reasonable manner based on the medium, means, and context in
which You Share the Licensed Material. For example, it may be
reasonable to satisfy the conditions by providing a URI or
hyperlink to a resource that includes the required
information.
3. If requested by the Licensor, You must remove any of the
information required by Section 3(a)(1)(A) to the extent
reasonably practicable.
4. If You Share Adapted Material You produce, the Adapter's
License You apply must not prevent recipients of the Adapted
Material from complying with this Public License.
Section 4 -- Sui Generis Database Rights.
Where the Licensed Rights include Sui Generis Database Rights that
apply to Your use of the Licensed Material:
a. for the avoidance of doubt, Section 2(a)(1) grants You the right
to extract, reuse, reproduce, and Share all or a substantial
portion of the contents of the database;
b. if You include all or a substantial portion of the database
contents in a database in which You have Sui Generis Database
Rights, then the database in which You have Sui Generis Database
Rights (but not its individual contents) is Adapted Material; and
c. You must comply with the conditions in Section 3(a) if You Share
all or a substantial portion of the contents of the database.
For the avoidance of doubt, this Section 4 supplements and does not
replace Your obligations under this Public License where the Licensed
Rights include other Copyright and Similar Rights.
Section 5 -- Disclaimer of Warranties and Limitation of Liability.
a. UNLESS OTHERWISE SEPARATELY UNDERTAKEN BY THE LICENSOR, TO THE
EXTENT POSSIBLE, THE LICENSOR OFFERS THE LICENSED MATERIAL AS-IS
AND AS-AVAILABLE, AND MAKES NO REPRESENTATIONS OR WARRANTIES OF
ANY KIND CONCERNING THE LICENSED MATERIAL, WHETHER EXPRESS,
IMPLIED, STATUTORY, OR OTHER. THIS INCLUDES, WITHOUT LIMITATION,
WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE, NON-INFRINGEMENT, ABSENCE OF LATENT OR OTHER DEFECTS,
ACCURACY, OR THE PRESENCE OR ABSENCE OF ERRORS, WHETHER OR NOT
KNOWN OR DISCOVERABLE. WHERE DISCLAIMERS OF WARRANTIES ARE NOT
ALLOWED IN FULL OR IN PART, THIS DISCLAIMER MAY NOT APPLY TO YOU.
b. TO THE EXTENT POSSIBLE, IN NO EVENT WILL THE LICENSOR BE LIABLE
TO YOU ON ANY LEGAL THEORY (INCLUDING, WITHOUT LIMITATION,
NEGLIGENCE) OR OTHERWISE FOR ANY DIRECT, SPECIAL, INDIRECT,
INCIDENTAL, CONSEQUENTIAL, PUNITIVE, EXEMPLARY, OR OTHER LOSSES,
COSTS, EXPENSES, OR DAMAGES ARISING OUT OF THIS PUBLIC LICENSE OR
USE OF THE LICENSED MATERIAL, EVEN IF THE LICENSOR HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH LOSSES, COSTS, EXPENSES, OR
DAMAGES. WHERE A LIMITATION OF LIABILITY IS NOT ALLOWED IN FULL OR
IN PART, THIS LIMITATION MAY NOT APPLY TO YOU.
c. The disclaimer of warranties and limitation of liability provided
above shall be interpreted in a manner that, to the extent
possible, most closely approximates an absolute disclaimer and
waiver of all liability.
Section 6 -- Term and Termination.
a. This Public License applies for the term of the Copyright and
Similar Rights licensed here. However, if You fail to comply with
this Public License, then Your rights under this Public License
terminate automatically.
b. Where Your right to use the Licensed Material has terminated under
Section 6(a), it reinstates:
1. automatically as of the date the violation is cured, provided
it is cured within 30 days of Your discovery of the
violation; or
2. upon express reinstatement by the Licensor.
For the avoidance of doubt, this Section 6(b) does not affect any
right the Licensor may have to seek remedies for Your violations
of this Public License.
c. For the avoidance of doubt, the Licensor may also offer the
Licensed Material under separate terms or conditions or stop
distributing the Licensed Material at any time; however, doing so
will not terminate this Public License.
d. Sections 1, 5, 6, 7, and 8 survive termination of this Public
License.
Section 7 -- Other Terms and Conditions.
a. The Licensor shall not be bound by any additional or different
terms or conditions communicated by You unless expressly agreed.
b. Any arrangements, understandings, or agreements regarding the
Licensed Material not stated herein are separate from and
independent of the terms and conditions of this Public License.
Section 8 -- Interpretation.
a. For the avoidance of doubt, this Public License does not, and
shall not be interpreted to, reduce, limit, restrict, or impose
conditions on any use of the Licensed Material that could lawfully
be made without permission under this Public License.
b. To the extent possible, if any provision of this Public License is
deemed unenforceable, it shall be automatically reformed to the
minimum extent necessary to make it enforceable. If the provision
cannot be reformed, it shall be severed from this Public License
without affecting the enforceability of the remaining terms and
conditions.
c. No term or condition of this Public License will be waived and no
failure to comply consented to unless expressly agreed to by the
Licensor.
d. Nothing in this Public License constitutes or may be interpreted
as a limitation upon, or waiver of, any privileges and immunities
that apply to the Licensor or You, including from the legal
processes of any jurisdiction or authority.
=======================================================================
Creative Commons is not a party to its public licenses.
Notwithstanding, Creative Commons may elect to apply one of its public
licenses to material it publishes and in those instances will be
considered the "Licensor." Except for the limited purpose of indicating
that material is shared under a Creative Commons public license or as
otherwise permitted by the Creative Commons policies published at
creativecommons.org/policies, Creative Commons does not authorize the
use of the trademark "Creative Commons" or any other trademark or logo
of Creative Commons without its prior written consent including,
without limitation, in connection with any unauthorized modifications
to any of its public licenses or any other arrangements,
understandings, or agreements concerning use of licensed material. For
the avoidance of doubt, this paragraph does not form part of the public
licenses.
Creative Commons may be contacted at creativecommons.org.

46
README.md
Unescape View File

@ -0,0 +1,46 @@
<a href="super-tiny-compiler.js"><img width="731" alt="THE SUPER TINY COMPILER" src="https://cloud.githubusercontent.com/assets/952783/14171276/ed7bf716-f6e6-11e5-96df-80a031c2769d.png"/></a>
***Welcome to The Super Tiny Compiler!***
This is an ultra-simplified example of all the major pieces of a modern compiler
written in easy to read JavaScript.
Reading through the guided code will help you learn about how *most* compilers
work from end to end.
### [Want to jump into the code? Click here](super-tiny-compiler.js)
---
### Why should I care?
That's fair, most people don't really have to think about compilers in their day
jobs. However, compilers are all around you, tons of the tools you use are based
on concepts borrowed from compilers.
### But compilers are scary!
Yes, they are. But that's our fault (the people who write compilers), we've
taken something that is reasonably straightforward and made it so scary that
most think of it as this totally unapproachable thing that only the nerdiest of
the nerds are able to understand.
### Okay so where do I begin?
Awesome! Head on over to the [super-tiny-compiler.js](super-tiny-compiler.js)
file.
### I'm back, that didn't make sense
Ouch, I'm really sorry. I'm planning on doing a lot more work on this to add
inline annotations. If you want to come back when that's done, you can either
watch/star this repo or follow me on
[twitter](https://twitter.com/thejameskyle) for updates.
### Tests
Run with `node test.js`
---
[![cc-by-4.0](https://licensebuttons.net/l/by/4.0/80x15.png)](http://creativecommons.org/licenses/by/4.0/)

937
super-tiny-compiler.js
Unescape View File

@ -0,0 +1,937 @@
/**
* TTTTTTTTTTTTTTTTTTTTTTTHHHHHHHHH HHHHHHHHHEEEEEEEEEEEEEEEEEEEEEE
* T:::::::::::::::::::::TH:::::::H H:::::::HE::::::::::::::::::::E
* T:::::::::::::::::::::TH:::::::H H:::::::HE::::::::::::::::::::E
* T:::::TT:::::::TT:::::THH::::::H H::::::HHEE::::::EEEEEEEEE::::E
* TTTTTT T:::::T TTTTTT H:::::H H:::::H E:::::E EEEEEE
* T:::::T H:::::H H:::::H E:::::E
* T:::::T H::::::HHHHH::::::H E::::::EEEEEEEEEE
* T:::::T H:::::::::::::::::H E:::::::::::::::E
* T:::::T H:::::::::::::::::H E:::::::::::::::E
* T:::::T H::::::HHHHH::::::H E::::::EEEEEEEEEE
* T:::::T H:::::H H:::::H E:::::E
* T:::::T H:::::H H:::::H E:::::E EEEEEE
* TT:::::::TT HH::::::H H::::::HHEE::::::EEEEEEEE:::::E
* T:::::::::T H:::::::H H:::::::HE::::::::::::::::::::E
* T:::::::::T H:::::::H H:::::::HE::::::::::::::::::::E
* TTTTTTTTTTT HHHHHHHHH HHHHHHHHHEEEEEEEEEEEEEEEEEEEEEE
*
* SSSSSSSSSSSSSSS UUUUUUUU UUUUUUUUPPPPPPPPPPPPPPPPP EEEEEEEEEEEEEEEEEEEEEERRRRRRRRRRRRRRRRR
* SS:::::::::::::::SU::::::U U::::::UP::::::::::::::::P E::::::::::::::::::::ER::::::::::::::::R
* S:::::SSSSSS::::::SU::::::U U::::::UP::::::PPPPPP:::::P E::::::::::::::::::::ER::::::RRRRRR:::::R
* S:::::S SSSSSSSUU:::::U U:::::UUPP:::::P P:::::PEE::::::EEEEEEEEE::::ERR:::::R R:::::R
* S:::::S U:::::U U:::::U P::::P P:::::P E:::::E EEEEEE R::::R R:::::R
* S:::::S U:::::U U:::::U P::::P P:::::P E:::::E R::::R R:::::R
* S::::SSSS U:::::U U:::::U P::::PPPPPP:::::P E::::::EEEEEEEEEE R::::RRRRRR:::::R
* SS::::::SSSSS U:::::U U:::::U P:::::::::::::PP E:::::::::::::::E R:::::::::::::RR
* SSS::::::::SS U:::::U U:::::U P::::PPPPPPPPP E:::::::::::::::E R::::RRRRRR:::::R
* SSSSSS::::S U:::::U U:::::U P::::P E::::::EEEEEEEEEE R::::R R:::::R
* S:::::S U:::::U U:::::U P::::P E:::::E R::::R R:::::R
* S:::::S U::::::U U::::::U P::::P E:::::E EEEEEE R::::R R:::::R
* SSSSSSS S:::::S U:::::::UUU:::::::U PP::::::PP EE::::::EEEEEEEE:::::ERR:::::R R:::::R
* S::::::SSSSSS:::::S UU:::::::::::::UU P::::::::P E::::::::::::::::::::ER::::::R R:::::R
* S:::::::::::::::SS UU:::::::::UU P::::::::P E::::::::::::::::::::ER::::::R R:::::R
* SSSSSSSSSSSSSSS UUUUUUUUU PPPPPPPPPP EEEEEEEEEEEEEEEEEEEEEERRRRRRRR RRRRRRR
*
* TTTTTTTTTTTTTTTTTTTTTTTIIIIIIIIIINNNNNNNN NNNNNNNNYYYYYYY YYYYYYY
* T:::::::::::::::::::::TI::::::::IN:::::::N N::::::NY:::::Y Y:::::Y
* T:::::::::::::::::::::TI::::::::IN::::::::N N::::::NY:::::Y Y:::::Y
* T:::::TT:::::::TT:::::TII::::::IIN:::::::::N N::::::NY::::::Y Y::::::Y
* TTTTTT T:::::T TTTTTT I::::I N::::::::::N N::::::NYYY:::::Y Y:::::YYY
* T:::::T I::::I N:::::::::::N N::::::N Y:::::Y Y:::::Y
* T:::::T I::::I N:::::::N::::N N::::::N Y:::::Y:::::Y
* T:::::T I::::I N::::::N N::::N N::::::N Y:::::::::Y
* T:::::T I::::I N::::::N N::::N:::::::N Y:::::::Y
* T:::::T I::::I N::::::N N:::::::::::N Y:::::Y
* T:::::T I::::I N::::::N N::::::::::N Y:::::Y
* T:::::T I::::I N::::::N N:::::::::N Y:::::Y
* TT:::::::TT II::::::IIN::::::N N::::::::N Y:::::Y
* T:::::::::T I::::::::IN::::::N N:::::::N YYYY:::::YYYY
* T:::::::::T I::::::::IN::::::N N::::::N Y:::::::::::Y
* TTTTTTTTTTT IIIIIIIIIINNNNNNNN NNNNNNN YYYYYYYYYYYYY
*
* CCCCCCCCCCCCC OOOOOOOOO MMMMMMMM MMMMMMMMPPPPPPPPPPPPPPPPP IIIIIIIIIILLLLLLLLLLL EEEEEEEEEEEEEEEEEEEEEERRRRRRRRRRRRRRRRR
* CCC::::::::::::C OO:::::::::OO M:::::::M M:::::::MP::::::::::::::::P I::::::::IL:::::::::L E::::::::::::::::::::ER::::::::::::::::R
* CC:::::::::::::::C OO:::::::::::::OO M::::::::M M::::::::MP::::::PPPPPP:::::P I::::::::IL:::::::::L E::::::::::::::::::::ER::::::RRRRRR:::::R
* C:::::CCCCCCCC::::CO:::::::OOO:::::::OM:::::::::M M:::::::::MPP:::::P P:::::PII::::::IILL:::::::LL EE::::::EEEEEEEEE::::ERR:::::R R:::::R
* C:::::C CCCCCCO::::::O O::::::OM::::::::::M M::::::::::M P::::P P:::::P I::::I L:::::L E:::::E EEEEEE R::::R R:::::R
* C:::::C O:::::O O:::::OM:::::::::::M M:::::::::::M P::::P P:::::P I::::I L:::::L E:::::E R::::R R:::::R
* C:::::C O:::::O O:::::OM:::::::M::::M M::::M:::::::M P::::PPPPPP:::::P I::::I L:::::L E::::::EEEEEEEEEE R::::RRRRRR:::::R
* C:::::C O:::::O O:::::OM::::::M M::::M M::::M M::::::M P:::::::::::::PP I::::I L:::::L E:::::::::::::::E R:::::::::::::RR
* C:::::C O:::::O O:::::OM::::::M M::::M::::M M::::::M P::::PPPPPPPPP I::::I L:::::L E:::::::::::::::E R::::RRRRRR:::::R
* C:::::C O:::::O O:::::OM::::::M M:::::::M M::::::M P::::P I::::I L:::::L E::::::EEEEEEEEEE R::::R R:::::R
* C:::::C O:::::O O:::::OM::::::M M:::::M M::::::M P::::P I::::I L:::::L E:::::E R::::R R:::::R
* C:::::C CCCCCCO::::::O O::::::OM::::::M MMMMM M::::::M P::::P I::::I L:::::L LLLLLL E:::::E EEEEEE R::::R R:::::R
* C:::::CCCCCCCC::::CO:::::::OOO:::::::OM::::::M M::::::MPP::::::PP II::::::IILL:::::::LLLLLLLLL:::::LEE::::::EEEEEEEE:::::ERR:::::R R:::::R
* CC:::::::::::::::C OO:::::::::::::OO M::::::M M::::::MP::::::::P I::::::::IL::::::::::::::::::::::LE::::::::::::::::::::ER::::::R R:::::R
* CCC::::::::::::C OO:::::::::OO M::::::M M::::::MP::::::::P I::::::::IL::::::::::::::::::::::LE::::::::::::::::::::ER::::::R R:::::R
* CCCCCCCCCCCCC OOOOOOOOO MMMMMMMM MMMMMMMMPPPPPPPPPP IIIIIIIIIILLLLLLLLLLLLLLLLLLLLLLLLEEEEEEEEEEEEEEEEEEEEEERRRRRRRR RRRRRRR
*
* =======================================================================================================================================================================
* =======================================================================================================================================================================
* =======================================================================================================================================================================
* =======================================================================================================================================================================
*/
/**
* Today we're going to write a compiler together. But not just any compiler... A
* super duper teeny tiny compiler! A compiler that is so small that if you
* remove all the comments this file would only be ~200 lines of actual code.
*
* We're going to compile some lisp-like function calls into some C-like
* function calls.
*
* If you are not familiar with one or the other. I'll just give you a quick intro.
*
* If we had two functions `add` and `subtract` they would be written like this:
*
* LISP C
*
* 2 + 2 (add 2 2) add(2, 2)
* 4 - 2 (subtract 4 2) subtract(4, 2)
* 2 + (4 - 2) (add 2 (subtract 4 2)) add(2, subtract(4, 2))
*
* Easy peezy right?
*
* Well good, because this is exactly what we are going to compile. While this
* is neither a complete LISP or C syntax, it will be enough of the syntax to
* demonstrate many of the major pieces of a modern compiler.
*/
/**
* Most compilers break down into three primary stages: Parsing, Transformation,
* and Code Generation
*
* 1. *Parsing* is taking raw code and turning it into a more abstract
* representation of the code.
*
* 2. *Transformation* takes this abstract representation and manipulates to do
* whatever the compiler wants it to.
*
* 3. *Code Generation* takes the transformed representation of the code and
* turns it into new code.
*/
/**
* Parsing
* -------
*
* Parsing typically gets broken down into two phases: Lexical Analysis and
* Syntactic Analysis.
*
* 1. *Lexical Analysis* takes the raw code and splits it apart into these things
* called tokens by a thing called a tokenizer (or lexer).
*
* Tokens are an array of tiny little objects that describe an isolated piece
* of the syntax. They could be numbers, labels, punctuation, operators,
* whatever.
*
* 2. *Syntactic Analysis* takes the tokens and reformats them into a
* representation that describes each part of the syntax and their relation
* to one another. This is known as an intermediate representation or
* Abstract Syntax Tree.
*
* An Abstract Syntax Tree, or AST for short, is a deeply nested object that
* represents code in a way that is both easy to work with and tells us a lot
* of information.
*
* For the following syntax:
*
* (add 2 (subtract 4 2))
*
* Tokens might look something like this:
*
* [
* { type: 'paren', value: '(' },
* { type: 'name', value: 'add' },
* { type: 'number', value: '2' },
* { type: 'paren', value: '(' },
* { type: 'name', value: 'subtract' },
* { type: 'number', value: '4' },
* { type: 'number', value: '2' },
* { type: 'paren', value: ')' },
* { type: 'paren', value: ')' }
* ]
*
* And an Abstract Syntax Tree (AST) might look like this:
*
* {
* type: 'Program',
* body: [{
* type: 'CallExpression',
* name: 'add',
* params: [{
* type: 'NumberLiteral',
* value: '2'
* }, {
* type: 'CallExpression',
* name: 'subtract',
* params: [{
* type: 'NumberLiteral',
* value: '4'
* }, {
* type: 'NumberLiteral',
* value: '2'
* }]
* }]
* }]
* }
*/
/**
* Transformation
* --------------
*
* The next type of stage for a compiler is transformation. Again, this just
* takes the AST from the last step and makes changes to it. It can manipulate
* the AST in the same language or it can translate it into an entirely new
* language.
*
* Let’s look at how we would transform an AST.
*
* You might notice that our AST has elements within it that look very similar.
* There are these objects with a type property. Each of these are known as an
* AST Node. These nodes have defined properties on them that describe one
* isolated part of the tree.
*
* We can have a node for a "NumberLiteral":
*
* {
* type: 'NumberLiteral',
* value: '2'
* }
*
* Or maybe a node for a "CallExpression":
*
* {
* type: 'CallExpression',
* name: 'subtract',
* params: [...nested nodes go here...]
* }
*
* When transforming the AST we can manipulate nodes by
* adding/removing/replacing properties, we can add new nodes, remove nodes, or
* we could leave the existing AST alone and create an entirely new one based
* on it.
*
* Since we’re targeting a new language, we’re going to focus on creating an
* entirely new AST that is specific to the target language.
*
* Traversal
* ---------
*
* In order to navigate through all of these nodes, we need to be able to
* traverse through them. This traversal process goes to each node in the AST
* depth-first.
*
* {
* type: 'Program',
* body: [{
* type: 'CallExpression',
* name: 'add',
* params: [{
* type: 'NumberLiteral',
* value: '2'
* }, {
* type: 'CallExpression',
* name: 'subtract',
* params: [{
* type: 'NumberLiteral',
* value: '4'
* }, {
* type: 'NumberLiteral',
* value: '2'
* }]
* }]
* }]
* }
*
* So for the above AST we would go:
*
* 1. Program - Starting at the top level of the AST
* 2. CallExpression (add) - Moving to the first element of the Program's body
* 3. NumberLiteral (2) - Moving to the first element of CallExpression's params
* 4. CallExpression (subtract) - Moving to the second element of CallExpression's params
* 5. NumberLiteral (4) - Moving to the first element of CallExpression's params
* 6. NumberLiteral (2) - Moving to the second element of CallExpression's params
*
* If we were manipulating this AST directly, instead of creating a separate AST,
* we would likely introduce all sorts of abstractions here. But just visiting
* each node in the tree is enough.
*
* The reason I use the word “visiting” is because there is this pattern of how
* to represent operations on elements of an object structure.
*
* Visitors
* --------
*
* The basic idea here is that we are going to create a “visitor” object that
* has methods that will accept different node types.
*
* var visitor = {
* NumberLiteral() {},
* CallExpression() {}
* };
*
* When we traverse our AST we will call the methods on this visitor whenever we
* encounter a node of a matching type.
*
* In order to make this useful we will also pass the node and a reference to
* the parent node.
*
* var visitor = {
* NumberLiteral(node, parent) {},
* CallExpression(node, parent) {}
* };
*/
/**
* Code Generation
* ---------------
*
* The final phase of a compiler is code generation. Sometimes compilers will do
* things that overlap with transformation, but for the most part code
* generation just means take our AST and string-ify code back out.
*
* Code generators work several different ways, some compilers will reuse the
* tokens from earlier, others will have created a separate representation of
* the code so that they can print node linearly, but from what I can tell most
* will use the same AST we just created, which is what we’re going to focus on.
*
* Effectively our code generator will know how to “print” all of the different
* node types of the AST, and it will recursively call itself to print nested
* nodes until everything is printed into one long string of code.
*/
/**
* And that's it! That's all the different pieces of a compiler.
*
* Now that isn’t to say every compiler looks exactly like I described here.
* Compilers serve many different purposes, and they might need more steps than
* I have detailed.
*
* But now you should have a general high-level idea of what most compilers look
* like.
*
* Now that I’ve explained all of this, you’re all good to go write your own
* compilers right?
*
* Just kidding, that's what I'm here to help with :P
*
* So let's begin...
*/
/**
* ============================================================================
* (/^▽^)/
* THE TOKENIZER!
* ============================================================================
*/
/**
* We're gonna start off with our first phase of parsing, lexical analysis, with
* the tokenizer.
*
* We're just going to take our string of code and break it down into an array
* of tokens.
*
* (add 2 (subtract 4 2)) => [{ type: 'paren', value: '(' }, ...]
*/
// We start by accepting an input string of code, and we're gonna set up two
// things...
function tokenizer(input) {
// A `current` variable for tracking our position in the code like a cursor.
var current = 0;
// And a `tokens` array for pushing our tokens to.
var tokens = [];
// We start by creating a `while` loop where we are setting up our `current`
// variable to be incremented as much as we want `inside` the loop.
//
// We do this because we may want to increment `current` many times within a
// single loop because our tokens can be any length.
while (current < input.length) {
// We're also going to store the `current` character in the `input`.
var char = input[current];
// The first thing we want to check for is an open parenthesis. This will
// later be used for `CallExpressions` but for now we only care about the
// character.
//
// We check to see if we have an open parenthesis:
if (char === '(') {
// If we do, we push a new token with the type `paren` and set the value
// to an open parenthesis.
tokens.push({
type: 'paren',
value: '('
});
// Then we increment `current`
current++;
// And we `continue` onto the next cycle of the loop.
continue;
}
// Next we're going to check for a closing parenthesis. We do the same exact
// thing as before: Check for a closing parenthesis, add a new token,
// increment `current`, and `continue`.
if (char === ')') {
tokens.push({
type: 'paren',
value: ')'
});
current++;
continue;
}
// Moving on, we're now going to check for whitespace. This is interesting
// because we care that whitespace exists to separate characters, but it
// isn't actually important for us to store as a token. We would only throw
// it out later.
//
// So here we're just going to test for existence and if it does exist we're
// going to just `continue` on.
var WHITESPACE = /\s/;
if (WHITESPACE.test(char)) {
current++;
continue;
}
// The next type of token is a number. This is different than what we have
// seen before because a number could be any number of characters and we
// want to capture the entire sequence of characters as one token.
//
// (add 123 456)
// ^^^ ^^^
// Only two separate tokens
//
// So we start this off when we encounter the first number in a sequence.
var NUMBERS = /[0-9]/;
if (NUMBERS.test(char)) {
// We're going to create a `value` string that we are going to push
// characters to.
var value = '';
// Then we're going to loop through each character in the sequence until
// we encounter a character that is not a number, pushing each character
// that is a number to our `value` and incrementing `current` as we go.
while (NUMBERS.test(char)) {
value += char;
char = input[++current];
}
// After that we push our `number` token to the `tokens` array.
tokens.push({
type: 'number',
value: value
});
// And we continue on.
continue;
}
// The last type of token will be a `name` token. This is a sequence of
// letters instead of numbers, that are the names of functions in our lisp
// syntax.
//
// (add 2 4)
// ^^^
// Name token
//
var LETTERS = /[a-z]/i;
if (LETTERS.test(char)) {
var value = '';
// Again we're just going to loop through all the letters pushing them to
// a value.
while (LETTERS.test(char)) {
value += char;
char = input[++current];
}
// And pushing that value as a token with the type `name` and continuing.
tokens.push({
type: 'name',
value: value
});
continue;
}
// Finally if we have not matched a character by now, we're going to throw
// an error and completely exit.
throw new TypeError('I dont know what this character is: ' + char);
}
// Then at the end of our `tokenizer` we simply return the tokens array.
return tokens;
}
/**
* ============================================================================
* ヽ/❀o ل͜ o\ﾉ
* THE PARSER!!!
* ============================================================================
*/
/**
* For our parser we're going to take our array of tokens and turn it into an
* AST.
*
* [{ type: 'paren', value: '(' }, ...] => { type: 'Program', body: [...] }
*/
// Okay, so we define a `parser` function that accepts our array of `tokens`.
function parser(tokens) {
// Again we keep a `current` variable that we will use as a cursor.
var current = 0;
// But this time we're going to use recursion instead of a `while` loop. So we
// define a `walk` function.
function walk() {
// Inside the walk function we start by grabbing the `current` token.
var token = tokens[current];
// We're going to split each type of token off into a different code path,
// starting off with `number` tokens.
//
// We test to see if we have a `number` token.
if (token.type === 'number') {
// If we have one, we'll increment `current`.
current++;
// And we'll return a new AST node called `NumberLiteral` and setting its
// value to the value of our token.
return {
type: 'NumberLiteral',
value: token.value
};
}
// Next we're going to look for CallExpressions. We start this off when we
// encounter an open parenthesis.
if (
token.type === 'paren' &&
token.value === '('
) {
// We'll increment `current` to skip the parenthesis since we don't care
// about it in our AST.
token = tokens[++current];
// We create a base node with the type `CallExpression`, and we're going
// to set the name as the current token's value since the next token after
// the open parenthesis is the name of the function.
var node = {
type: 'CallExpression',
name: token.value,
params: []
};
// We increment `current` *again* to skip the name token.
token = tokens[++current];
// And now we want to loop through each token that will be the `params` of
// our `CallExpression` until we encounter a closing parenthesis.
//
// Now this is where recursion comes in. Instead of trying to parse a
// potentially infinitely nested set of nodes we're going to rely on
// recursion to resolve things.
//
// To explain this, let's take our Lisp code. You can see that the
// parameters of the `add` are a number and a nested `CallExpression` that
// includes its own numbers.
//
// (add 2 (subtract 4 2))
//
// You'll also notice that in our tokens array we have multiple closing
// parenthesis.
//
// [
// { type: 'paren', value: '(' },
// { type: 'name', value: 'add' },
// { type: 'number', value: '2' },
// { type: 'paren', value: '(' },
// { type: 'name', value: 'subtract' },
// { type: 'number', value: '4' },
// { type: 'number', value: '2' },
// { type: 'paren', value: ')' }, <<< Closing parenthesis
// { type: 'paren', value: ')' } <<< Closing parenthesis
// ]
//
// We're going to rely on the nested `walk` function to increment our
// `current` variable past any nested `CallExpressions`.
// So we create a `while` loop that will continue until it encounters a
// token with a `type` of `'paren'` and a `value` of a closing
// parenthesis.
while (
(token.type !== 'paren') ||
(token.type === 'paren' && token.value !== ')')
) {
// we'll call the `walk` function which will return a `node` and we'll
// push it into our `node.params`.
node.params.push(walk());
token = tokens[current];
}
// Finally we will increment `current` one last time to skip the closing
// parenthesis.
current++;
// And return the node.
return node;
}
// Again, if we haven't recognized the token type by now we're going to
// throw an error.
throw new TypeError(token.type);
}
// Now, we're going to create our AST which will have a root which is a
// `Program` node.
var ast = {
type: 'Program',
body: []
};
// And we're going to kickstart our `walk` function, pushing nodes to our
// `ast.body` array.
//
// The reason we are doing this inside a loop is because our program can have
// `CallExpressions` after one another instead of being nested.
//
// (add 2 2)
// (subtract 4 2)
//
while (current < tokens.length) {
ast.body.push(walk());
}
// At the end of our parser we'll return the AST.
return ast;
}
/**
* ============================================================================
* ⌒(❀>◞౪◟<❀)⌒
* THE TRAVERSER!!!
* ============================================================================
*/
/**
* So now we have our AST, and we want to be able to visit different nodes with
* a visitor. We need to be able to call the methods on the visitor whenever we
* encounter a node with a matching type.
*
* traverse(ast, {
* Program(node, parent) {
* // ...
* },
*
* CallExpression(node, parent) {
* // ...
* },
*
* NumberLiteral(node, parent) {
* // ...
* }
* });
*/
// So we define a traverser function which accepts an AST and a
// visitor. Inside we're going to define two functions...
function traverser(ast, visitor) {
// A `traverseArray` function that will allow us to iterate over an array and
// call the next function that we will define: `traverseNode`.
function traverseArray(array, parent) {
array.forEach(function(child) {
traverseNode(child, parent);
});
}
// `traverseNode` will accept a `node` and its `parent` node. So that it can
// pass both to our visitor methods.
function traverseNode(node, parent) {
// We start by testing for the existence of a method on the visitor with a
// matching `type`.
var method = visitor[node.type];
// If it exists we'll call it with the `node` and its `parent`.
if (method) {
method(node, parent);
}
// Next we are going to split things up by the current node type.
switch (node.type) {
// We'll start with our top level `Program`. Since Program nodes have a
// property named body that has an array of nodes, we will call
// `traverseArray` to traverse down into them.
//
// (Remember that `traverseArray` will in turn call `traverseNode` so we
// are causing the tree to be traversed recursively)
case 'Program':
traverseArray(node.body, node);
break;
// Next we do the same with `CallExpressions` and traverse their `params`.
case 'CallExpression':
traverseArray(node.params, node);
break;
// In the case of `NumberLiterals` we don't have any child nodes to visit,
// so we'll just break.
case 'NumberLiteral':
break;
// And again, if we haven't recognized the node type then we'll throw an
// error.
default:
throw new TypeError(node.type);
}
}
// Finally we kickstart the traverser by calling `traverseNode` with our ast
// with no `parent` because the top level of the AST doesn't have a parent.
traverseNode(ast, null);
}
/**
* ============================================================================
* ⁽(◍˃̵͈̑ᴗ˂̵͈̑)⁽
* THE TRANSFORMER!!!
* ============================================================================
*/
/**
* Next up, the transformer. Our transformer is going to take the AST that we
* have built and pass it to our traverser function with a visitor and will
* create a new ast.
*
* ----------------------------------------------------------------------------
* Original AST | Transformed AST
* ----------------------------------------------------------------------------
* { | {
* type: 'Program', | type: 'Program',
* body: [{ | body: [{
* type: 'CallExpression', | type: 'ExpressionStatement',
* name: 'add', | expression: {
* params: [{ | type: 'CallExpression',
* type: 'NumberLiteral', | callee: {
* value: '2' | type: 'Identifier',
* }, { | name: 'add'
* type: 'CallExpression', | },
* name: 'subtract', | arguments: [{
* params: [{ | type: 'NumberLiteral',
* type: 'NumberLiteral', | value: '2'
* value: '4' | }, {
* }, { | type: 'CallExpression',
* type: 'NumberLiteral', | callee: {
* value: '2' | type: 'Identifier',
* }] | name: 'subtract'
* }] | },
* }] | arguments: [{
* } | type: 'NumberLiteral',
* | value: '4'
* ---------------------------------- | }, {
* | type: 'NumberLiteral',
* | value: '2'
* | }]
* (sorry the other one is longer.) | }
* | }
* | }]
* | }
* ----------------------------------------------------------------------------
*/
// So we have our transformer function which will accept the lisp ast.
function transformer(ast) {
// We'll create a `newAst` which like our previous AST will have a program
// node.
var newAst = {
type: 'Program',
body: []
};
// Next I'm going to cheat a little and create a bit of a hack. We're going to
// use a property named `context` on our parent nodes that we're going to push
// nodes to their parent's `context`. Normally you would have a better
// abstraction than this, but for our purposes this keeps things simple.
//
// Just take note that the context is a reference *from* the old ast *to* the
// new ast.
ast._context = newAst.body;
// We'll start by calling the traverser function with our ast and a visitor.
traverser(ast, {
// The first visitor method accepts `NumberLiterals`
NumberLiteral: function(node, parent) {
// We'll create a new node also named `NumberLiteral` that we will push to
// the parent context.
parent._context.push({
type: 'NumberLiteral',
value: node.value
});
},
// Next up, `CallExpressions`.
CallExpression: function(node, parent) {
// We start creating a new node `CallExpression` with a nested
// `Identifier`.
var expression = {
type: 'CallExpression',
callee: {
type: 'Identifier',
name: node.name
},
arguments: []
};
// Next we're going to define a new context on the original
// `CallExpression` node that will reference the `expression`'s arguments
// so that we can push arguments.
node._context = expression.arguments;
// Then we're going to check if the parent node is a `CallExpression`.
// If it is not...
if (parent.type !== 'CallExpression') {
// We're going to wrap our `CallExpression` node with an
// `ExpressionStatement`. We do this because the top level
// `CallExpressions` in JavaScript are actually statements.
expression = {
type: 'ExpressionStatement',
expression: expression
};
}
// Last, we push our (possibly wrapped) `CallExpression` to the `parent`'s
// `context`.
parent._context.push(expression);
}
});
// At the end of our transformer function we'll return the new ast that we
// just created.
return newAst;
}
/**
* ============================================================================
* ヾ（〃＾∇＾）ﾉ♪
* THE CODE GENERATOR!!!!
* ============================================================================
*/
/**
* Now let's move onto our last phase: The Code Generator.
*
* Our code generator is going to recursively call itself to print each node in
* the tree into one giant string.
*/
function codeGenerator(node) {
// We'll break things down by the `type` of the `node`.
switch (node.type) {
// If we have a `Program` node. We will map through each node in the `body`
// and run them through the code generator and join them with a newline.
case 'Program':
return node.body.map(codeGenerator)
.join('\n');
// For `ExpressionStatements` we'll call the code generator on the nested
// expression and we'll add a semicolon...
case 'ExpressionStatement':
return (
codeGenerator(node.expression) +
';' // << (...because we like to code the *correct* way)
);
// For `CallExpressions` we will print the `callee`, add an open
// parenthesis, we'll map through each node in the `arguments` array and run
// them through the code generator, joining them with a comma, and then
// we'll add a closing parenthesis.
case 'CallExpression':
return (
codeGenerator(node.callee) +
'(' +
node.arguments.map(codeGenerator)
.join(', ') +
')'
);
// For `Identifiers` we'll just return the `node`'s name.
case 'Identifier':
return node.name;
// For `NumberLiterals` we'll just return the `node`'s value.
case 'NumberLiteral':
return node.value;
// And if we haven't recognized the node, we'll throw an error.
default:
throw new TypeError(node.type);
}
}
/**
* ============================================================================
* (۶* ‘ヮ’)۶”
* !!!!!!!!THE COMPILER!!!!!!!!
* ============================================================================
*/
/**
* FINALLY! We'll create our `compiler` function. Here we will link together
* every part of the pipeline.
*
* 1. input => tokenizer => tokens
* 2. tokens => parser => ast
* 3. ast => transformer => newAst
* 4. newAst => generator => output
*/
function compiler(input) {
var tokens = tokenizer(input);
var ast = parser(tokens);
var newAst = transformer(ast);
var output = codeGenerator(newAst);
// and simply return the output!
return output;
}
/**
* ============================================================================
* (๑˃̵ᴗ˂̵)و
* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!YOU MADE IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
* ============================================================================
*/
// Now I'm just exporting everything...
module.exports = {
tokenizer: tokenizer,
parser: parser,
transformer: transformer,
codeGenerator: codeGenerator,
compiler: compiler
};

84
test.js
Unescape View File

@ -0,0 +1,84 @@
var superTinyCompiler = require('./super-tiny-compiler');
var assert = require('assert');
var tokenizer = superTinyCompiler.tokenizer;
var parser = superTinyCompiler.parser;
var transformer = superTinyCompiler.transformer;
var codeGenerator = superTinyCompiler.codeGenerator;
var compiler = superTinyCompiler.compiler;
var input = '(add 2 (subtract 4 2))';
var output = 'add(2, subtract(4, 2));';
var tokens = [
{ type: 'paren', value: '(' },
{ type: 'name', value: 'add' },
{ type: 'number', value: '2' },
{ type: 'paren', value: '(' },
{ type: 'name', value: 'subtract' },
{ type: 'number', value: '4' },
{ type: 'number', value: '2' },
{ type: 'paren', value: ')' },
{ type: 'paren', value: ')' }
];
var ast = {
type: 'Program',
body: [{
type: 'CallExpression',
name: 'add',
params: [{
type: 'NumberLiteral',
value: '2'
}, {
type: 'CallExpression',
name: 'subtract',
params: [{
type: 'NumberLiteral',
value: '4'
}, {
type: 'NumberLiteral',
value: '2'
}]
}]
}]
};
var newAst = {
type: 'Program',
body: [{
type: 'ExpressionStatement',
expression: {
type: 'CallExpression',
callee: {
type: 'Identifier',
name: 'add'
},
arguments: [{
type: 'NumberLiteral',
value: '2'
}, {
type: 'CallExpression',
callee: {
type: 'Identifier',
name: 'subtract'
},
arguments: [{
type: 'NumberLiteral',
value: '4'
}, {
type: 'NumberLiteral',
value: '2'
}]
}]
}
}]
};
assert.deepStrictEqual(tokenizer(input), tokens, 'Tokenizer should turn `input` string into `tokens` array');
assert.deepStrictEqual(parser(tokens), ast, 'Parser should turn `tokens` array into `ast`');
assert.deepStrictEqual(transformer(ast), newAst, 'Transformer should turn `ast` into a `newAst`');
assert.deepStrictEqual(codeGenerator(newAst), output, 'Code Generator should turn `newAst` into `output` string');
assert.deepStrictEqual(compiler(input), output, 'Compiler should turn `input` into `output`');
console.log('All Passed!');
Write Preview
Loading…
Cancel
Save