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jashkenas--coffeescript
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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.

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
View File

@ -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]