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jamiebuilds_the-super-tiny-.../super-tiny-compiler.js

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Give Super Tiny Compiler
2016-03-30 22:22:59 +00:00
/**
* 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
fix(super-tiny-compiler): Ds that should have been Us are now Us and not Ds fixes #1
2016-03-30 23:34:24 +00:00
* 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
Give Super Tiny Compiler
2016-03-30 22:22:59 +00:00
* 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
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* T:::::T I::::I N::::::N N::::N:::::::N Y:::::::Y
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* 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
*
* =======================================================================================================================================================================
* =======================================================================================================================================================================
* =======================================================================================================================================================================
* =======================================================================================================================================================================
*/
Init code comments
2016-03-31 00:39:16 +00:00
/**
* Today we're going write a compiler together. But not just any compiler... A
* super duper tiny teeny 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.
*
not familiar instead of familiar
2016-03-31 21:31:39 +00:00
* If you are not familiar with one or the other. I'll just give you a quick intro.
Init code comments
2016-03-31 00:39:16 +00:00
*
* 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 major pieces of a modern compiler.
*/
/**
* Most compiler 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 of 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 and 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...
*/
/**
* -----------------------------------------------------------------------------
* *Note:* This is all I've written so far, so the code below isn't annnotated
* yet. You can still read it all and it totally works, but I plan on improving
* this in the near future
* -----------------------------------------------------------------------------
*/
Give Super Tiny Compiler
2016-03-30 22:22:59 +00:00
/**
* ============================================================================
* (/^▽^)/
* THE TOKENIZER!
* ============================================================================
*/
function tokenizer(input) {
var current = 0;
var tokens = [];
while (current < input.length) {
var char = input[current];
if (char === '(') {
tokens.push({
type: 'paren',
value: '('
});
current++;
continue;
}
if (char === ')') {
tokens.push({
type: 'paren',
value: ')'
});
current++;
continue;
}
var WHITESPACE = /\s/;
if (WHITESPACE.test(char)) {
current++;
continue;
}
var NUMBERS = /[0-9]/;
if (NUMBERS.test(char)) {
var value = '';
while (NUMBERS.test(char)) {
value += char;
char = input[++current];
}
tokens.push({
type: 'number',
value: value
});
continue;
}
var LETTERS = /[a-zA-Z]/;
if (LETTERS.test(char)) {
var value = '';
while (LETTERS.test(char)) {
value += char;
char = input[++current];
}
tokens.push({
type: 'name',
value: value
});
continue;
}
throw new TypeError('I dont know what this character is: ' + char);
}
return tokens;
}
/**
* ============================================================================
* ヽ/❀o ل͜ o\ﾉ
* THE PARSER!!!
* ============================================================================
*/
function parser(tokens) {
var current = 0;
function walk() {
var token = tokens[current];
if (token.type === 'number') {
current++;
return {
type: 'NumberLiteral',
value: token.value
};
}
if (
token.type === 'paren' &&
token.value === '('
) {
current++;
var node = {
type: 'CallExpression',
name: tokens[current].value,
params: []
};
current++;
while (
token.type !== 'paren' ||
token.value !== ')'
) {
node.params.push(walk());
token = tokens[current];
}
current++;
return node;
}
throw new TypeError(token.type);
}
var program = {
type: 'Program',
body: []
};
while (current < tokens.length) {
program.body.push(walk());
}
return program;
}
/**
* ============================================================================
* ⌒(❀>◞౪◟<❀)⌒
* THE TRAVERSER!!!
* ============================================================================
*/
function traverser(program, visitor) {
function traverseArray(array, parent) {
array.forEach(function(child) {
traverseNode(child, parent);
});
}
function traverseNode(node, parent) {
var method = visitor[node.type];
if (method) {
method(node, parent);
}
switch (node.type) {
case 'Program':
traverseArray(node.body, node);
break;
case 'CallExpression':
traverseArray(node.params, node);
break;
case 'NumberLiteral':
break;
default:
throw new TypeError(node.type);
}
}
traverseNode(program, null);
}
/**
* ============================================================================
* ⁽(◍˃̵͈̑ᴗ˂̵͈̑)⁽
* THE TRANSFORMER!!!
* ============================================================================
*/
function transformer(program) {
var ast = {
type: 'Program',
body: []
};
program._context = ast.body;
traverser(program, {
NumberLiteral: function(node, parent) {
parent._context.push({
type: 'NumberLiteral',
value: node.value
});
},
CallExpression: function(node, parent) {
var expression = {
type: 'CallExpression',
callee: {
type: 'Identifier',
name: node.name
},
arguments: []
};
node._context = expression.arguments;
if (parent.type !== 'CallExpression') {
expression = {
type: 'ExpressionStatement',
expression: expression
};
}
parent._context.push(expression);
}
});
return ast;
}
/**
* ============================================================================
* ヾ（〃＾∇＾）ﾉ♪
* THE CODE GENERATOR!!!!
* ============================================================================
*/
function codeGenerator(node) {
switch (node.type) {
case 'Program':
return node.body.map(codeGenerator)
.join('\n');
case 'ExpressionStatement':
return (
codeGenerator(node.expression) +
';'
);
case 'CallExpression':
return (
codeGenerator(node.callee) +
'(' +
node.arguments.map(codeGenerator)
.join(', ') +
')'
);
case 'Identifier':
return node.name;
case 'NumberLiteral':
return node.value;
default:
throw new TypeError(node.type);
}
}
/**
* ============================================================================
* (۶* ‘ヮ’)۶”
* !!!!!!!!THE COMPILER!!!!!!!!
* ============================================================================
*/
function compiler(input) {
var tokens = tokenizer(input);
var ast = parser(tokens);
var newAst = transformer(ast);
var output = codeGenerator(newAst);
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
};
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