mirror of
https://github.com/jashkenas/coffeescript.git
synced 2022-11-09 12:23:24 -05:00
463 lines
17 KiB
JavaScript
463 lines
17 KiB
JavaScript
(function(){
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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, Lexer, MULTILINER, MULTI_DENT, NOT_REGEX, NO_NEWLINE, NUMBER, OPERATOR, REGEX, RESERVED, Rewriter, STRING, STRING_NEWLINES, WHITESPACE, count, include;
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// The CoffeeScript Lexer. Uses a series of token-matching regexes to attempt
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// matches against the beginning of the source code. When a match is found,
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// a token is produced, we consume the match, and start again. Tokens are in the
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// form:
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//
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// [tag, value, line_number]
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//
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// Which is a format that can be fed directly into [Jison](http://github.com/zaach/jison).
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// Set up the Lexer for both Node.js and the browser, depending on where we are.
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if ((typeof process !== "undefined" && process !== null)) {
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Rewriter = require('./rewriter').Rewriter;
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} else {
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this.exports = this;
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Rewriter = this.Rewriter;
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}
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// Constants
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// ---------
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// Keywords that CoffeeScript shares in common with JavaScript.
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JS_KEYWORDS = ["if", "else", "true", "false", "new", "return", "try", "catch", "finally", "throw", "break", "continue", "for", "in", "while", "delete", "instanceof", "typeof", "switch", "super", "extends", "class"];
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// CoffeeScript-only keywords, which we're more relaxed about allowing. They can't
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// be used standalone, but you can reference them as an attached property.
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COFFEE_KEYWORDS = ["then", "unless", "yes", "no", "on", "off", "and", "or", "is", "isnt", "not", "of", "by", "where", "when"];
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// The combined list of keywords is the superset that gets passed verbatim to
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// the parser.
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KEYWORDS = JS_KEYWORDS.concat(COFFEE_KEYWORDS);
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// The list of keywords that are reserved by JavaScript, but not used, or are
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// used by CoffeeScript internally. We throw an error when these are encountered,
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// to avoid having a JavaScript error at runtime.
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RESERVED = ["case", "default", "do", "function", "var", "void", "with", "const", "let", "debugger", "enum", "export", "import", "native", "__extends", "__hasProp"];
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// The superset of both JavaScript keywords and reserved words, none of which may
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// be used as identifiers or properties.
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JS_FORBIDDEN = JS_KEYWORDS.concat(RESERVED);
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// Token matching regexes.
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IDENTIFIER = /^([a-zA-Z$_](\w|\$)*)/;
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NUMBER = /^(\b((0(x|X)[0-9a-fA-F]+)|([0-9]+(\.[0-9]+)?(e[+\-]?[0-9]+)?)))\b/i;
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STRING = /^(""|''|"([\s\S]*?)([^\\]|\\\\)"|'([\s\S]*?)([^\\]|\\\\)')/;
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HEREDOC = /^("{6}|'{6}|"{3}\n?([\s\S]*?)\n?([ \t]*)"{3}|'{3}\n?([\s\S]*?)\n?([ \t]*)'{3})/;
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JS = /^(``|`([\s\S]*?)([^\\]|\\\\)`)/;
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OPERATOR = /^([+\*&|\/\-%=<>:!?]+)/;
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WHITESPACE = /^([ \t]+)/;
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COMMENT = /^(((\n?[ \t]*)?#[^\n]*)+)/;
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CODE = /^((-|=)>)/;
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REGEX = /^(\/(\S.*?)?([^\\]|\\\\)\/[imgy]{0,4})/;
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MULTI_DENT = /^((\n([ \t]*))+)(\.)?/;
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LAST_DENTS = /\n([ \t]*)/g;
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LAST_DENT = /\n([ \t]*)/;
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ASSIGNMENT = /^(:|=)$/;
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// Token cleaning regexes.
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JS_CLEANER = /(^`|`$)/g;
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MULTILINER = /\n/g;
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STRING_NEWLINES = /\n[ \t]*/g;
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COMMENT_CLEANER = /(^[ \t]*#|\n[ \t]*$)/mg;
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NO_NEWLINE = /^([+\*&|\/\-%=<>:!.\\][<>=&|]*|and|or|is|isnt|not|delete|typeof|instanceof)$/;
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HEREDOC_INDENT = /^[ \t]+/mg;
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// Tokens which a regular expression will never immediately follow, but which
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// a division operator might.
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//
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// See: http://www.mozilla.org/js/language/js20-2002-04/rationale/syntax.html#regular-expressions
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//
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// Our list is shorter, due to sans-parentheses method calls.
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NOT_REGEX = ['NUMBER', 'REGEX', '++', '--', 'FALSE', 'NULL', 'TRUE'];
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// Tokens which could legitimately be invoked or indexed. A opening
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// parentheses or bracket following these tokens will be recorded as the start
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// of a function invocation or indexing operation.
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CALLABLE = ['IDENTIFIER', 'SUPER', ')', ']', '}', 'STRING', '@'];
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// Tokens that indicate an access -- keywords immediately following will be
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// treated as identifiers.
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ACCESSORS = ['PROPERTY_ACCESS', 'PROTOTYPE_ACCESS', 'SOAK_ACCESS', '@'];
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// Tokens that, when immediately preceding a `WHEN`, indicate that the `WHEN`
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// occurs at the start of a line. We disambiguate these from trailing whens to
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// avoid an ambiguity in the grammar.
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BEFORE_WHEN = ['INDENT', 'OUTDENT', 'TERMINATOR'];
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// The Lexer Class
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// ---------------
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// The Lexer class reads a stream of CoffeeScript and divvys it up into tagged
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// tokens. A minor bit of the ambiguity in the grammar has been avoided by
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// pushing some extra smarts into the Lexer.
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exports.Lexer = (function() {
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Lexer = function Lexer() { };
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// Scan by attempting to match tokens one at a time. Slow and steady.
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Lexer.prototype.tokenize = function tokenize(code) {
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this.code = code;
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// The remainder of the source code.
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this.i = 0;
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// Current character position we're parsing.
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this.line = 1;
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// The current line.
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this.indent = 0;
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// The current indent level.
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this.indents = [];
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// The stack of all indent levels we are currently within.
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this.tokens = [];
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// Collection of all parsed tokens in the form ['TOKEN_TYPE', value, line]
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while (this.i < this.code.length) {
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this.chunk = this.code.slice(this.i);
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this.extract_next_token();
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}
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this.close_indentation();
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return (new Rewriter()).rewrite(this.tokens);
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};
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// At every position, run through this list of attempted matches,
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// short-circuiting if any of them succeed.
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Lexer.prototype.extract_next_token = function extract_next_token() {
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if (this.identifier_token()) {
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return null;
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}
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if (this.number_token()) {
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return null;
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}
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if (this.heredoc_token()) {
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return null;
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}
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if (this.string_token()) {
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return null;
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}
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if (this.js_token()) {
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return null;
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}
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if (this.regex_token()) {
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return null;
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}
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if (this.line_token()) {
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return null;
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}
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if (this.comment_token()) {
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return null;
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}
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if (this.whitespace_token()) {
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return null;
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}
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return this.literal_token();
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};
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// Tokenizers
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// ----------
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// Matches identifying literals: variables, keywords, method names, etc.
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Lexer.prototype.identifier_token = function identifier_token() {
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var id, tag;
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if (!((id = this.match(IDENTIFIER, 1)))) {
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return false;
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}
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this.name_access_type();
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tag = 'IDENTIFIER';
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if (include(KEYWORDS, id) && !(include(ACCESSORS, this.tag(0)) && !this.prev().spaced)) {
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tag = id.toUpperCase();
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}
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if (include(RESERVED, id)) {
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this.identifier_error(id);
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}
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if (tag === 'WHEN' && include(BEFORE_WHEN, this.tag())) {
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tag = 'LEADING_WHEN';
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}
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this.token(tag, id);
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this.i += id.length;
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return true;
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};
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// Matches numbers, including decimals, hex, and exponential notation.
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Lexer.prototype.number_token = function number_token() {
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var number;
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if (!((number = this.match(NUMBER, 1)))) {
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return false;
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}
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this.token('NUMBER', number);
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this.i += number.length;
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return true;
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};
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// Matches strings, including multi-line strings.
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Lexer.prototype.string_token = function string_token() {
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var escaped, string;
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if (!((string = this.match(STRING, 1)))) {
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return false;
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}
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escaped = string.replace(STRING_NEWLINES, " \\\n");
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this.token('STRING', escaped);
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this.line += count(string, "\n");
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this.i += string.length;
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return true;
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};
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// Matches heredocs, adjusting indentation to the correct level.
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Lexer.prototype.heredoc_token = function heredoc_token() {
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var doc, match;
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if (!((match = this.chunk.match(HEREDOC)))) {
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return false;
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}
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doc = this.sanitize_heredoc(match[2] || match[4]);
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this.token('STRING', '"' + doc + '"');
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this.line += count(match[1], "\n");
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this.i += match[1].length;
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return true;
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};
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// Matches interpolated JavaScript.
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Lexer.prototype.js_token = function js_token() {
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var script;
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if (!((script = this.match(JS, 1)))) {
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return false;
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}
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this.token('JS', script.replace(JS_CLEANER, ''));
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this.i += script.length;
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return true;
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};
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// Matches regular expression literals.
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Lexer.prototype.regex_token = function regex_token() {
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var regex;
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if (!((regex = this.match(REGEX, 1)))) {
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return false;
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}
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if (include(NOT_REGEX, this.tag())) {
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return false;
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}
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this.token('REGEX', regex);
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this.i += regex.length;
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return true;
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};
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// Matches and conumes comments.
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Lexer.prototype.comment_token = function comment_token() {
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var comment;
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if (!((comment = this.match(COMMENT, 1)))) {
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return false;
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}
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this.line += (comment.match(MULTILINER) || []).length;
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this.token('COMMENT', comment.replace(COMMENT_CLEANER, '').split(MULTILINER));
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this.token('TERMINATOR', "\n");
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this.i += comment.length;
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return true;
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};
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// Matches newlines, indents, and outdents, and determines which is which.
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Lexer.prototype.line_token = function line_token() {
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var diff, indent, next_character, no_newlines, prev, size;
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if (!((indent = this.match(MULTI_DENT, 1)))) {
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return false;
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}
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this.line += indent.match(MULTILINER).length;
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this.i += indent.length;
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prev = this.prev(2);
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size = indent.match(LAST_DENTS).reverse()[0].match(LAST_DENT)[1].length;
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next_character = this.chunk.match(MULTI_DENT)[4];
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no_newlines = next_character === '.' || (this.value() && this.value().match(NO_NEWLINE) && prev && (prev[0] !== '.') && !this.value().match(CODE));
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if (size === this.indent) {
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if (no_newlines) {
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return this.suppress_newlines(indent);
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}
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return this.newline_token(indent);
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} else if (size > this.indent) {
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if (no_newlines) {
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return this.suppress_newlines(indent);
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}
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diff = size - this.indent;
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this.token('INDENT', diff);
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this.indents.push(diff);
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} else {
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this.outdent_token(this.indent - size, no_newlines);
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}
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this.indent = size;
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return true;
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};
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// Record an outdent token or tokens, if we happen to be moving back inwards
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// past multiple recorded indents.
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Lexer.prototype.outdent_token = function outdent_token(move_out, no_newlines) {
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var last_indent;
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while (move_out > 0 && this.indents.length) {
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last_indent = this.indents.pop();
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this.token('OUTDENT', last_indent);
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move_out -= last_indent;
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}
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if (!(this.tag() === 'TERMINATOR' || no_newlines)) {
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this.token('TERMINATOR', "\n");
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}
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return true;
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};
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// Matches and consumes non-meaningful whitespace. Tag the previous token
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// as being "spaced", because there are some cases where it makes a difference.
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Lexer.prototype.whitespace_token = function whitespace_token() {
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var prev, space;
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if (!((space = this.match(WHITESPACE, 1)))) {
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return false;
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}
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prev = this.prev();
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if (prev) {
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prev.spaced = true;
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}
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this.i += space.length;
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return true;
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};
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// Generate a newline token. Multiple newlines get merged together.
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Lexer.prototype.newline_token = function newline_token(newlines) {
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if (!(this.tag() === 'TERMINATOR')) {
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this.token('TERMINATOR', "\n");
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}
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return true;
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};
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// Use a `\` at a line-ending to suppress the newline.
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// The slash is removed here once its job is done.
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Lexer.prototype.suppress_newlines = function suppress_newlines(newlines) {
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if (this.value() === "\\") {
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this.tokens.pop();
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}
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return true;
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};
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// We treat all other single characters as a token. Eg.: `( ) , . !`
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// Multi-character operators are also literal tokens, so that Jison can assign
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// the proper order of operations.
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Lexer.prototype.literal_token = function literal_token() {
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var match, not_spaced, tag, value;
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match = this.chunk.match(OPERATOR);
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value = match && match[1];
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if (value && value.match(CODE)) {
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this.tag_parameters();
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}
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value = value || this.chunk.substr(0, 1);
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not_spaced = !this.prev() || !this.prev().spaced;
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tag = value;
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if (value.match(ASSIGNMENT)) {
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tag = 'ASSIGN';
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if (include(JS_FORBIDDEN, this.value)) {
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this.assignment_error();
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}
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} else if (value === ';') {
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tag = 'TERMINATOR';
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} else if (value === '[' && this.tag() === '?' && not_spaced) {
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tag = 'SOAKED_INDEX_START';
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this.soaked_index = true;
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this.tokens.pop();
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} else if (value === ']' && this.soaked_index) {
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tag = 'SOAKED_INDEX_END';
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this.soaked_index = false;
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} else if (include(CALLABLE, this.tag()) && not_spaced) {
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if (value === '(') {
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tag = 'CALL_START';
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}
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if (value === '[') {
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tag = 'INDEX_START';
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}
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}
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this.token(tag, value);
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this.i += value.length;
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return true;
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};
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// Token Manipulators
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// ------------------
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// As we consume a new `IDENTIFIER`, look at the previous token to determine
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// if it's a special kind of accessor.
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Lexer.prototype.name_access_type = function name_access_type() {
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if (this.value() === '::') {
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this.tag(1, 'PROTOTYPE_ACCESS');
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}
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if (this.value() === '.' && !(this.value(2) === '.')) {
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if (this.tag(2) === '?') {
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this.tag(1, 'SOAK_ACCESS');
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return this.tokens.splice(-2, 1);
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} else {
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return this.tag(1, 'PROPERTY_ACCESS');
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}
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}
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};
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// Sanitize a heredoc by escaping double quotes and erasing all external
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// indentation on the left-hand side.
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Lexer.prototype.sanitize_heredoc = function sanitize_heredoc(doc) {
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var indent;
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indent = (doc.match(HEREDOC_INDENT) || ['']).sort()[0];
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return doc.replace(new RegExp("^" + indent, 'gm'), '').replace(MULTILINER, "\\n").replace(/"/g, '\\"');
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};
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// A source of ambiguity in our grammar was parameter lists in function
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// definitions (as opposed to argument lists in function calls). Tag
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// parameter identifiers in order to avoid this. Also, parameter lists can
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// make use of splats.
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Lexer.prototype.tag_parameters = function tag_parameters() {
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var _a, i, tok;
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if (this.tag() !== ')') {
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return null;
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}
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i = 0;
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while (true) {
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i += 1;
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tok = this.prev(i);
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if (!tok) {
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return null;
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}
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if ((_a = tok[0]) === 'IDENTIFIER') {
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tok[0] = 'PARAM';
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} else if (_a === ')') {
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tok[0] = 'PARAM_END';
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} else if (_a === '(') {
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return (tok[0] = 'PARAM_START');
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}
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}
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return true;
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};
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// Close up all remaining open blocks at the end of the file.
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Lexer.prototype.close_indentation = function close_indentation() {
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return this.outdent_token(this.indent);
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};
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// Error for when you try to use a forbidden word in JavaScript as
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// an identifier.
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Lexer.prototype.identifier_error = function identifier_error(word) {
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throw new Error('SyntaxError: Reserved word "' + word + '" on line ' + this.line);
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};
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// Error for when you try to assign to a reserved word in JavaScript,
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// like "function" or "default".
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Lexer.prototype.assignment_error = function assignment_error() {
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throw new Error('SyntaxError: Reserved word "' + this.value() + '" on line ' + this.line + ' can\'t be assigned');
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};
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// Helpers
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// -------
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// Add a token to the results, taking note of the line number.
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Lexer.prototype.token = function token(tag, value) {
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return this.tokens.push([tag, value, this.line]);
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};
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// Peek at a tag in the current token stream.
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Lexer.prototype.tag = function tag(index, tag) {
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var tok;
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if (!((tok = this.prev(index)))) {
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return null;
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}
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if ((typeof tag !== "undefined" && tag !== null)) {
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return (tok[0] = tag);
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}
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return tok[0];
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};
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// Peek at a value in the current token stream.
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Lexer.prototype.value = function value(index, val) {
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var tok;
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if (!((tok = this.prev(index)))) {
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return null;
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}
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if ((typeof val !== "undefined" && val !== null)) {
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return (tok[1] = val);
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}
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return tok[1];
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};
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// Peek at a previous token, entire.
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Lexer.prototype.prev = function prev(index) {
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return this.tokens[this.tokens.length - (index || 1)];
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};
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// Attempt to match a string against the current chunk, returning the indexed
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// match if successful, and `false` otherwise.
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Lexer.prototype.match = function match(regex, index) {
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var m;
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if (!((m = this.chunk.match(regex)))) {
|
|
return false;
|
|
}
|
|
return m ? m[index] : false;
|
|
};
|
|
return Lexer;
|
|
}).call(this);
|
|
// Utility Functions
|
|
// -----------------
|
|
// Does a list include a value?
|
|
include = function include(list, value) {
|
|
return list.indexOf(value) >= 0;
|
|
};
|
|
// Count the number of occurences of a character in a string.
|
|
count = function count(string, letter) {
|
|
var num, pos;
|
|
num = 0;
|
|
pos = string.indexOf(letter);
|
|
while (pos !== -1) {
|
|
num += 1;
|
|
pos = string.indexOf(letter, pos + 1);
|
|
}
|
|
return num;
|
|
};
|
|
})();
|