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carefully categorizing JS keywords from JS reserved words from Coffee keywords, so that we can throw syntax errors at compile time if JS keywords are getting assigned to.

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This commit is contained in:
Jeremy Ashkenas 2010-02-18 20:09:41 -05:00
parent 28a8c05513
commit d4a180c413
2 changed files with 39 additions and 12 deletions
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18
lib/lexer.js
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@ -1,5 +1,5 @@
(function(){
var ACCESSORS, ASSIGNMENT, BEFORE_WHEN, CALLABLE, CODE, COMMENT, COMMENT_CLEANER, HEREDOC, HEREDOC_INDENT, IDENTIFIER, JS, JS_CLEANER, KEYWORDS, LAST_DENT, LAST_DENTS, MULTILINER, MULTI_DENT, NOT_REGEX, NO_NEWLINE, NUMBER, OPERATOR, REGEX, RESERVED, Rewriter, STRING, STRING_NEWLINES, WHITESPACE, lex;
var ACCESSORS, ASSIGNMENT, BEFORE_WHEN, CALLABLE, CODE, COFFEE_KEYWORDS, COMMENT, COMMENT_CLEANER, HEREDOC, HEREDOC_INDENT, IDENTIFIER, JS, JS_CLEANER, JS_FORBIDDEN, JS_KEYWORDS, KEYWORDS, LAST_DENT, LAST_DENTS, MULTILINER, MULTI_DENT, NOT_REGEX, NO_NEWLINE, NUMBER, OPERATOR, REGEX, RESERVED, Rewriter, STRING, STRING_NEWLINES, WHITESPACE, lex;
if ((typeof process !== "undefined" && process !== null)) {
Rewriter = require('./rewriter').Rewriter;
} else {
@ -11,11 +11,17 @@
// pushing some extra smarts into the Lexer.
exports.Lexer = (lex = function lex() { });
// Constants ============================================================
// Keywords that CoffeScript shares in common with JS.
JS_KEYWORDS = ["if", "else", "true", "false", "new", "return", "try", "catch", "finally", "throw", "break", "continue", "for", "in", "while", "delete", "instanceof", "typeof", "switch", "super", "extends"];
// CoffeeScript-only keywords -- which we're more relaxed about allowing.
COFFEE_KEYWORDS = ["then", "unless", "yes", "no", "on", "off", "and", "or", "is", "isnt", "not", "of", "by", "where", "when"];
// The list of keywords passed verbatim to the parser.
KEYWORDS = ["if", "else", "then", "unless", "true", "false", "yes", "no", "on", "off", "and", "or", "is", "isnt", "not", "new", "return", "try", "catch", "finally", "throw", "break", "continue", "for", "in", "of", "by", "where", "while", "delete", "instanceof", "typeof", "switch", "when", "super", "extends"];
KEYWORDS = JS_KEYWORDS.concat(COFFEE_KEYWORDS);
// The list of keywords that are reserved by JavaScript, but not used, and aren't
// used by CoffeeScript. Using these will throw an error at compile time.
RESERVED = ["case", "default", "do", "function", "var", "void", "with", "class", "const", "let", "debugger", "enum", "export", "import", "native"];
// JavaScript keywords and reserved words together, excluding CoffeeScript ones.
JS_FORBIDDEN = JS_KEYWORDS.concat(RESERVED);
// Token matching regexes. (keep the IDENTIFIER regex in sync with AssignNode.)
IDENTIFIER = /^([a-zA-Z$_](\w|\$)*)/;
NUMBER = /^(\b((0(x|X)[0-9a-fA-F]+)|([0-9]+(\.[0-9]+)?(e[+\-]?[0-9]+)?)))\b/i;
@ -286,7 +292,13 @@
this.tag_parameters();
}
value = value || this.chunk.substr(0, 1);
tag = value.match(ASSIGNMENT) ? 'ASSIGN' : value;
tag = value;
if (value.match(ASSIGNMENT)) {
tag = 'ASSIGN';
if (JS_FORBIDDEN.indexOf(this.value()) >= 0) {
throw new Error('SyntaxError: Reserved word "' + this.value() + '" on line ' + this.line + ' can\'t be assigned');
}
}
if (value === ';') {
tag = 'TERMINATOR';
}

33
src/lexer.coffee
View file

@ -11,20 +11,29 @@ exports.Lexer: lex: ->
# Constants ============================================================
# The list of keywords passed verbatim to the parser.
KEYWORDS: [
"if", "else", "then", "unless",
"true", "false", "yes", "no", "on", "off",
"and", "or", "is", "isnt", "not",
# Keywords that CoffeScript shares in common with JS.
JS_KEYWORDS: [
"if", "else",
"true", "false",
"new", "return",
"try", "catch", "finally", "throw",
"break", "continue",
"for", "in", "of", "by", "where", "while",
"for", "in", "while",
"delete", "instanceof", "typeof",
"switch", "when",
"super", "extends"
"switch", "super", "extends"
]
# CoffeeScript-only keywords -- which we're more relaxed about allowing.
COFFEE_KEYWORDS: [
"then", "unless",
"yes", "no", "on", "off",
"and", "or", "is", "isnt", "not",
"of", "by", "where", "when"
]
# The list of keywords passed verbatim to the parser.
KEYWORDS: JS_KEYWORDS.concat COFFEE_KEYWORDS
# The list of keywords that are reserved by JavaScript, but not used, and aren't
# used by CoffeeScript. Using these will throw an error at compile time.
RESERVED: [
@ -32,6 +41,9 @@ RESERVED: [
"const", "let", "debugger", "enum", "export", "import", "native"
]
# JavaScript keywords and reserved words together, excluding CoffeeScript ones.
JS_FORBIDDEN: JS_KEYWORDS.concat RESERVED
# Token matching regexes. (keep the IDENTIFIER regex in sync with AssignNode.)
IDENTIFIER : /^([a-zA-Z$_](\w|\$)*)/
NUMBER : /^(\b((0(x|X)[0-9a-fA-F]+)|([0-9]+(\.[0-9]+)?(e[+\-]?[0-9]+)?)))\b/i
@ -233,7 +245,10 @@ lex::literal_token: ->
value: match and match[1]
@tag_parameters() if value and value.match(CODE)
value ||= @chunk.substr(0, 1)
tag: if value.match(ASSIGNMENT) then 'ASSIGN' else value
tag: value
if value.match(ASSIGNMENT)
tag: 'ASSIGN'
throw new Error('SyntaxError: Reserved word "' + @value() + '" on line ' + @line + ' can\'t be assigned') if JS_FORBIDDEN.indexOf(@value()) >= 0
tag: 'TERMINATOR' if value == ';'
prev: @tokens[@tokens.length - 1]