Implement assign and set commands, improve output format

src/vm/commands/assign.ts

@@ -0,0 +1,30 @@
+import {Command, ParseContext, StrTerm} from "./command.js";
+import {Awaitable} from "../../util/types.js";
+import {LexInput} from "../lexer.js";
+import {StrVM} from "../vm.js";
+
+export type AssignData = {
+    value: StrTerm,
+}
+
+export class Assign extends Command<AssignData> {
+    attemptParse(context: ParseContext): Awaitable<AssignData> {
+        return {
+            value: context.popTerm(),
+        }
+    }
+
+    isParseCandidate(token: LexInput): boolean {
+        return this.isKeyword(token, '=') || this.isKeyword(token, 'assign')
+    }
+
+    getDisplayName(): string {
+        return '='
+    }
+
+    execute(vm: StrVM, data: AssignData): Awaitable<StrVM> {
+        return vm.replaceContextMatchingTerm(ctx => ({
+            override: ctx.resolveRequired(data.value),
+        }))
+    }
+}

src/vm/commands/command.ts

@@ -1,5 +1,5 @@
 import {createHash} from 'node:crypto';
-import {LexInput} from '../lexer.js'
+import {LexInput, tokenIsLVal} from '../lexer.js'
 import {
     Executable,
     ExpectedEndOfInputError,
@@ -203,8 +203,7 @@ export class ParseContext {
         }
 
         const input = this.inputs.shift()!
-
-        if ( input.literal || !input.value.match(/^\$[a-zA-Z0-9_]+$/) ) {
+        if ( !tokenIsLVal(input) ) {
             throw new InvalidVariableNameError(`Expected variable name. Found: ${input.value}`)
         }
 
@@ -217,6 +216,15 @@ export type CommandData = Record<string, unknown>
 export abstract class Command<TData extends CommandData> {
     abstract isParseCandidate(token: LexInput): boolean
 
+    /**
+     * If true, the first token in the command will be included in the ParseContext for attemptParse(...).
+     * For normal commands, this is omitted (since it is always just the name of the command).
+     * However, some advanced commands (like the `$x = foo` form of `set`) require the leader to be included.
+     */
+    shouldIncludeLeaderInParseContext(): boolean {
+        return false
+    }
+
     abstract attemptParse(context: ParseContext): Awaitable<TData>
 
     abstract getDisplayName(): string
@@ -228,4 +236,8 @@ export abstract class Command<TData extends CommandData> {
     protected isKeyword(token: LexInput, keyword: string): boolean {
         return !token.literal && token.value === keyword
     }
+
+    protected isLVal(token: LexInput): boolean {
+        return tokenIsLVal(token)
+    }
 }

src/vm/commands/index.ts

@@ -43,9 +43,12 @@ import {Each} from "./each.js";
 import {Words} from "./words.js";
 import {Drop} from "./drop.js";
 import {Sort} from "./sort.js";
+import {Set} from "./set.js";
+import {Assign} from "./assign.js";
 
 export type Commands = Command<CommandData>[]
 export const commands: Commands = [
+    new Assign,
     new Clear,
     new Contains,
     new Copy,
@@ -78,6 +81,7 @@ export const commands: Commands = [
     new RSub,
     new RunFile,
     new Save,
+    new Set,
     new Show,
     new Sort,
     new Split,

src/vm/commands/set.ts

@@ -0,0 +1,55 @@
+import {Command, isStrLVal, ParseContext, StrLVal, StrTerm} from "./command.js";
+import {Awaitable} from "../../util/types.js";
+import {LexInput} from "../lexer.js";
+import {StrVM} from "../vm.js";
+
+export type SetData = {
+    lval: StrLVal,
+    rval: StrTerm,
+}
+
+/**
+ * This command has 2 forms:
+ * set $x foo
+ * $x = foo
+ */
+export class Set extends Command<SetData> {
+    attemptParse(context: ParseContext): Awaitable<SetData> {
+        const term = context.peekTerm()!
+        if ( term.term === 'string' && !term.literal && term.value === 'set' ) {
+            // We got the `set $x foo` form of the command:
+            context.popKeywordInSet(['set'])
+            return {
+                lval: context.popLVal(),
+                rval: context.popTerm(),
+            }
+        }
+
+        // Otherwise, we got the `$x = foo` form of the command:
+        const lval = context.popLVal()
+        context.popKeywordInSet(['='])
+        return {
+            lval,
+            rval: context.popTerm(),
+        }
+    }
+
+    getDisplayName(): string {
+        return 'set'
+    }
+
+    isParseCandidate(token: LexInput): boolean {
+        return this.isKeyword(token, 'set') || this.isLVal(token)
+    }
+
+    /** @override Since the leader might be the lval (for `$x = foo` form), we need it to be included. */
+    shouldIncludeLeaderInParseContext(): boolean {
+        return true
+    }
+
+    execute(vm: StrVM, data: SetData): Awaitable<StrVM> {
+        return vm.tapInPlace(ctx =>
+            ctx.inScope(s =>
+                s.setOrShadowValue(data.lval, ctx.resolveRequired(data.rval))))
+    }
+}

src/vm/lexer.ts

@@ -17,6 +17,9 @@ const LITERAL_MAP: Record<string, string> = {
     's': ' ',
 }
 
+export const tokenIsLVal = (input: LexInput): boolean =>
+    !input.literal && !!input.value.match(/^\$[a-zA-Z0-9_]+$/)
+
 export class Lexer extends BehaviorSubject<LexToken> {
     private isEscape: boolean = false
     private inQuote?: '"'|"'"

src/vm/output.ts

@@ -5,19 +5,31 @@ import fs from "node:fs";
 import {tempFile} from "../util/fs.js";
 
 export const getSubjectDisplay = (sub: StrRVal): string => {
+    let annotated = '\n┌───────────────\n'
     if ( sub.term === 'string' ) {
         const lines = sub.value.split('\n')
         const padLength = `${lines.length}`.length  // heh
-        return lines
-            .map((line, idx) => idx.toString().padStart(padLength, ' ') + ' ⎸' + line)
+        annotated += lines
+            .map((line, idx) => '│ ' + idx.toString().padStart(padLength, ' ') + ' │' + line)
             .join('\n')
     }
 
     if ( sub.term === 'int' ) {
-        return String(sub.term)
+        annotated += `│ ${sub.value}`
     }
 
-    return JSON.stringify(sub.value, null, '\t')  // fixme
+    if ( sub.term === 'destructured' ) {
+        const padLength = `${sub.value.length}`.length
+        annotated += sub.value
+            .map((el, idx) => '│ ' + idx.toString().padStart(padLength, ' ') + ' │'
+                + el.value.split('\n').map((line, lineIdx) => lineIdx ? (`│ ${''.padStart(padLength, ' ')} │${line}`) : line).join('\n'))
+            .join('\n│ ' + ''.padStart(padLength, ' ') + ' ┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈\n')
+    }
+
+    annotated += '\n├───────────────'
+    annotated += `\n│ :: ${sub.term}`
+    annotated += '\n└───────────────'
+    return annotated
 }
 
 export type Display = {
@@ -27,7 +39,7 @@ export type Display = {
 
 export class ConsoleDisplay implements Display {
     showSubject(sub: StrRVal) {
-        console.log(`\n---------------\n${getSubjectDisplay(sub)}\n---------------\n`)
+        console.log(getSubjectDisplay(sub))
     }
 
     showRaw(str: string) {

src/vm/parser.ts

@@ -38,6 +38,9 @@ export class Parser extends BehaviorSubject<Executable<CommandData>> {
             }
 
             this.parseCandidate = this.getParseCandidate(token)
+            if ( this.parseCandidate.shouldIncludeLeaderInParseContext() ) {
+                this.inputForCandidate.push(token)
+            }
             return
         }