Implement take command and comments (--) + misc cleanup

src/vm/lexer.ts

@@ -22,6 +22,7 @@ export const tokenIsLVal = (input: LexInput): boolean =>
 
 export class Lexer extends BehaviorSubject<LexToken> {
     private isEscape: boolean = false
+    private inComment: boolean = false
     private inQuote?: '"'|"'"
     private tokenAccumulator: string = ''
 
@@ -57,6 +58,11 @@ export class Lexer extends BehaviorSubject<LexToken> {
             const c = inputChars.shift()!
             this.logState(c)
 
+            // We're in a comment. Ignore everything except newlines.
+            if ( this.inComment && c !== '\n' ) {
+                continue
+            }
+
             // We got the 2nd character after an escape
             if ( this.isEscape ) {
                 this.tokenAccumulator += LITERAL_MAP[c] || c
@@ -75,6 +81,7 @@ export class Lexer extends BehaviorSubject<LexToken> {
                 if ( this.tokenAccumulator ) {
                     await this.emitToken('terminator')
                 }
+                this.inComment = false
                 await this.next({ type: 'terminator' })
                 continue
             }
@@ -87,6 +94,13 @@ export class Lexer extends BehaviorSubject<LexToken> {
                 continue
             }
 
+            // Comments start with --
+            if ( this.tokenAccumulator === '-' && c === '-' && !this.inQuote ) {
+                this.tokenAccumulator = ''
+                this.inComment = true
+                continue
+            }
+
             // We are either starting or ending an unescaped matching quote.
             // For now, only parse single quotes. Makes it nicer to type " in commands.
             if ( c === `'` ) {