mirror of
https://github.com/jashkenas/coffeescript.git
synced 2022-11-09 12:23:24 -05:00
372 lines
15 KiB
JavaScript
372 lines
15 KiB
JavaScript
(function(){
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var BALANCED_PAIRS, EXPRESSION_CLOSE, EXPRESSION_END, EXPRESSION_START, IMPLICIT_BLOCK, IMPLICIT_CALL, IMPLICIT_END, IMPLICIT_FUNC, INVERSES, Rewriter, SINGLE_CLOSERS, SINGLE_LINERS, _a, _b, _c, _d, _e, _f, _g, _h, _i, _j, _k, helpers, include, pair;
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var __slice = Array.prototype.slice, __bind = function(func, obj, args) {
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return function() {
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return func.apply(obj || {}, args ? args.concat(__slice.call(arguments, 0)) : arguments);
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};
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}, __hasProp = Object.prototype.hasOwnProperty;
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// The CoffeeScript language has a good deal of optional syntax, implicit syntax,
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// and shorthand syntax. This can greatly complicate a grammar and bloat
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// the resulting parse table. Instead of making the parser handle it all, we take
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// a series of passes over the token stream, using this **Rewriter** to convert
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// shorthand into the unambiguous long form, add implicit indentation and
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// parentheses, balance incorrect nestings, and generally clean things up.
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// Set up exported variables for both Node.js and the browser.
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if ((typeof process !== "undefined" && process !== null)) {
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helpers = require('./helpers').helpers;
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} else {
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this.exports = this;
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helpers = this.helpers;
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}
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// Import the helpers we need.
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include = helpers.include;
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// The **Rewriter** class is used by the [Lexer](lexer.html), directly against
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// its internal array of tokens.
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exports.Rewriter = (function() {
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Rewriter = function Rewriter() { };
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// Rewrite the token stream in multiple passes, one logical filter at
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// a time. This could certainly be changed into a single pass through the
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// stream, with a big ol' efficient switch, but it's much nicer to work with
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// like this. The order of these passes matters -- indentation must be
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// corrected before implicit parentheses can be wrapped around blocks of code.
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Rewriter.prototype.rewrite = function rewrite(tokens) {
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this.tokens = tokens;
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this.adjust_comments();
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this.remove_leading_newlines();
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this.remove_mid_expression_newlines();
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this.close_open_calls_and_indexes();
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this.add_implicit_indentation();
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this.add_implicit_parentheses();
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this.ensure_balance(BALANCED_PAIRS);
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this.rewrite_closing_parens();
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return this.tokens;
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};
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// Rewrite the token stream, looking one token ahead and behind.
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// Allow the return value of the block to tell us how many tokens to move
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// forwards (or backwards) in the stream, to make sure we don't miss anything
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// as tokens are inserted and removed, and the stream changes length under
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// our feet.
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Rewriter.prototype.scan_tokens = function scan_tokens(block) {
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var i, move;
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i = 0;
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while (true) {
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if (!(this.tokens[i])) {
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break;
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}
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move = block(this.tokens[i - 1], this.tokens[i], this.tokens[i + 1], i);
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i += move;
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}
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return true;
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};
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// Massage newlines and indentations so that comments don't have to be
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// correctly indented, or appear on a line of their own.
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Rewriter.prototype.adjust_comments = function adjust_comments() {
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return this.scan_tokens(__bind(function(prev, token, post, i) {
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var after;
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if (!(token[0] === 'COMMENT')) {
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return 1;
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}
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after = this.tokens[i + 2];
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if (after && after[0] === 'INDENT') {
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this.tokens.splice(i + 2, 1);
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this.tokens.splice(i, 0, after);
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return 1;
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} else if (prev && prev[0] !== 'TERMINATOR' && prev[0] !== 'INDENT' && prev[0] !== 'OUTDENT') {
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this.tokens.splice(i, 0, ['TERMINATOR', "\n", prev[2]]);
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return 2;
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} else {
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return 1;
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}
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}, this));
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};
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// Leading newlines would introduce an ambiguity in the grammar, so we
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// dispatch them here.
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Rewriter.prototype.remove_leading_newlines = function remove_leading_newlines() {
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var _a;
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_a = [];
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while (this.tokens[0] && this.tokens[0][0] === 'TERMINATOR') {
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_a.push(this.tokens.shift());
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}
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return _a;
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};
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// Some blocks occur in the middle of expressions -- when we're expecting
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// this, remove their trailing newlines.
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Rewriter.prototype.remove_mid_expression_newlines = function remove_mid_expression_newlines() {
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return this.scan_tokens(__bind(function(prev, token, post, i) {
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if (!(post && include(EXPRESSION_CLOSE, post[0]) && token[0] === 'TERMINATOR')) {
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return 1;
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}
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this.tokens.splice(i, 1);
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return 0;
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}, this));
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};
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// The lexer has tagged the opening parenthesis of a method call, and the
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// opening bracket of an indexing operation. Match them with their paired
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// close.
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Rewriter.prototype.close_open_calls_and_indexes = function close_open_calls_and_indexes() {
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var brackets, parens;
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parens = [0];
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brackets = [0];
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return this.scan_tokens(__bind(function(prev, token, post, i) {
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var _a;
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if ((_a = token[0]) === 'CALL_START') {
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parens.push(0);
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} else if (_a === 'INDEX_START') {
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brackets.push(0);
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} else if (_a === '(') {
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parens[parens.length - 1] += 1;
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} else if (_a === '[') {
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brackets[brackets.length - 1] += 1;
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} else if (_a === ')') {
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if (parens[parens.length - 1] === 0) {
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parens.pop();
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token[0] = 'CALL_END';
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} else {
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parens[parens.length - 1] -= 1;
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}
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} else if (_a === ']') {
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if (brackets[brackets.length - 1] === 0) {
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brackets.pop();
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token[0] = 'INDEX_END';
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} else {
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brackets[brackets.length - 1] -= 1;
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}
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}
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return 1;
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}, this));
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};
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// Methods may be optionally called without parentheses, for simple cases.
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// Insert the implicit parentheses here, so that the parser doesn't have to
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// deal with them.
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Rewriter.prototype.add_implicit_parentheses = function add_implicit_parentheses() {
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var calls, parens, stack, start_parens;
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stack = [0];
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calls = 0;
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parens = 0;
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start_parens = 0;
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return this.scan_tokens(__bind(function(prev, token, post, i) {
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var _a, _b, _c, idx, last, open, size, stack_pointer, tag, tmp;
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tag = token[0];
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if (tag === 'CALL_START') {
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calls += 1;
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} else if (tag === 'CALL_END') {
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calls -= 1;
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} else if (tag === '(') {
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parens += 1;
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} else if (tag === ')') {
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parens -= 1;
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} else if (tag === 'INDENT') {
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stack.push(0);
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} else if (tag === 'OUTDENT') {
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last = stack.pop();
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stack[stack.length - 1] += last;
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}
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open = stack[stack.length - 1] > 0;
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if (!(typeof post !== "undefined" && post !== null) || (start_parens > parens) || (parens === 0 && include(IMPLICIT_END, tag))) {
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if (tag === 'INDENT' && prev && include(IMPLICIT_BLOCK, prev[0])) {
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return 1;
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}
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if (tag === 'OUTDENT' && token.generated) {
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return 1;
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}
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if (open || tag === 'INDENT') {
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idx = tag === 'OUTDENT' ? i + 1 : i;
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stack_pointer = tag === 'INDENT' ? 2 : 1;
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_b = 0; _c = stack[stack.length - stack_pointer];
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for (_a = 0, tmp = _b; (_b <= _c ? tmp < _c : tmp > _c); (_b <= _c ? tmp += 1 : tmp -= 1), _a++) {
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this.tokens.splice(idx, 0, ['CALL_END', ')', token[2]]);
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}
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size = stack[stack.length - stack_pointer] + 1;
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stack[stack.length - stack_pointer] = 0;
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return size;
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}
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}
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if (!(prev && include(IMPLICIT_FUNC, prev[0]) && include(IMPLICIT_CALL, tag))) {
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return 1;
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}
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calls = 0;
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start_parens = tag === '(' ? parens - 1 : parens;
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this.tokens.splice(i, 0, ['CALL_START', '(', token[2]]);
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stack[stack.length - 1] += 1;
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return 2;
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}, this));
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};
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// Because our grammar is LALR(1), it can't handle some single-line
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// expressions that lack ending delimiters. The **Rewriter** adds the implicit
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// blocks, so it doesn't need to. ')' can close a single-line block,
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// but we need to make sure it's balanced.
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Rewriter.prototype.add_implicit_indentation = function add_implicit_indentation() {
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return this.scan_tokens(__bind(function(prev, token, post, i) {
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var idx, insertion, outdent, parens, pre, starter, tok;
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if (!(include(SINGLE_LINERS, token[0]) && post[0] !== 'INDENT' && !(token[0] === 'ELSE' && post[0] === 'IF'))) {
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return 1;
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}
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starter = token[0];
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this.tokens.splice(i + 1, 0, ['INDENT', 2, token[2]]);
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idx = i + 1;
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parens = 0;
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while (true) {
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idx += 1;
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tok = this.tokens[idx];
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pre = this.tokens[idx - 1];
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if ((!tok || (include(SINGLE_CLOSERS, tok[0]) && tok[1] !== ';') || (tok[0] === ')' && parens === 0)) && !(starter === 'ELSE' && tok[0] === 'ELSE')) {
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insertion = pre[0] === "," ? idx - 1 : idx;
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outdent = ['OUTDENT', 2, token[2]];
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outdent.generated = true;
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this.tokens.splice(insertion, 0, outdent);
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break;
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}
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if (tok[0] === '(') {
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parens += 1;
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}
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if (tok[0] === ')') {
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parens -= 1;
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}
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}
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if (!(token[0] === 'THEN')) {
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return 1;
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}
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this.tokens.splice(i, 1);
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return 0;
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}, this));
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};
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// Ensure that all listed pairs of tokens are correctly balanced throughout
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// the course of the token stream.
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Rewriter.prototype.ensure_balance = function ensure_balance(pairs) {
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var _a, _b, key, levels, line, open, open_line, unclosed, value;
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levels = {};
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open_line = {};
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this.scan_tokens(__bind(function(prev, token, post, i) {
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var _a, _b, _c, _d, close, open, pair;
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_b = pairs;
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for (_a = 0, _c = _b.length; _a < _c; _a++) {
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pair = _b[_a];
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_d = pair;
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open = _d[0];
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close = _d[1];
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levels[open] = levels[open] || 0;
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if (token[0] === open) {
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if (levels[open] === 0) {
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open_line[open] = token[2];
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}
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levels[open] += 1;
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}
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if (token[0] === close) {
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levels[open] -= 1;
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}
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if (levels[open] < 0) {
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throw new Error("too many " + (token[1]) + " on line " + (token[2] + 1));
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}
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}
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return 1;
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}, this));
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unclosed = (function() {
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_a = []; _b = levels;
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for (key in _b) { if (__hasProp.call(_b, key)) {
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value = _b[key];
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value > 0 ? _a.push(key) : null;
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}}
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return _a;
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}).call(this);
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if (unclosed.length) {
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open = unclosed[0];
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line = open_line[open] + 1;
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throw new Error("unclosed " + open + " on line " + line);
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}
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};
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// We'd like to support syntax like this:
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// el.click((event) ->
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// el.hide())
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// In order to accomplish this, move outdents that follow closing parens
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// inwards, safely. The steps to accomplish this are:
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// 1. Check that all paired tokens are balanced and in order.
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// 2. Rewrite the stream with a stack: if you see an `EXPRESSION_START`, add it
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// to the stack. If you see an `EXPRESSION_END`, pop the stack and replace
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// it with the inverse of what we've just popped.
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// 3. Keep track of "debt" for tokens that we manufacture, to make sure we end
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// up balanced in the end.
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Rewriter.prototype.rewrite_closing_parens = function rewrite_closing_parens() {
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var _a, debt, key, stack, val;
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stack = [];
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debt = {};
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_a = INVERSES;
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for (key in _a) { if (__hasProp.call(_a, key)) {
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val = _a[key];
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(debt[key] = 0);
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}}
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return this.scan_tokens(__bind(function(prev, token, post, i) {
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var inv, match, mtag, tag;
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tag = token[0];
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inv = INVERSES[token[0]];
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if (include(EXPRESSION_START, tag)) {
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stack.push(token);
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return 1;
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} else if (include(EXPRESSION_END, tag)) {
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if (debt[inv] > 0) {
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debt[inv] -= 1;
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this.tokens.splice(i, 1);
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return 0;
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} else {
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match = stack.pop();
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mtag = match[0];
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if (tag === INVERSES[mtag]) {
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return 1;
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}
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debt[mtag] += 1;
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val = mtag === 'INDENT' ? match[1] : INVERSES[mtag];
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this.tokens.splice(i, 0, [INVERSES[mtag], val]);
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return 1;
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}
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} else {
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return 1;
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}
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}, this));
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};
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return Rewriter;
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}).call(this);
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// Constants
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// ---------
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// List of the token pairs that must be balanced.
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BALANCED_PAIRS = [['(', ')'], ['[', ']'], ['{', '}'], ['INDENT', 'OUTDENT'], ['PARAM_START', 'PARAM_END'], ['CALL_START', 'CALL_END'], ['INDEX_START', 'INDEX_END'], ['SOAKED_INDEX_START', 'SOAKED_INDEX_END']];
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// The inverse mappings of `BALANCED_PAIRS` we're trying to fix up, so we can
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// look things up from either end.
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INVERSES = {};
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_b = BALANCED_PAIRS;
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for (_a = 0, _c = _b.length; _a < _c; _a++) {
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pair = _b[_a];
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INVERSES[pair[0]] = pair[1];
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INVERSES[pair[1]] = pair[0];
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}
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// The tokens that signal the start of a balanced pair.
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EXPRESSION_START = (function() {
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_d = []; _f = BALANCED_PAIRS;
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for (_e = 0, _g = _f.length; _e < _g; _e++) {
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pair = _f[_e];
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_d.push(pair[0]);
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}
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return _d;
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}).call(this);
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// The tokens that signal the end of a balanced pair.
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EXPRESSION_END = (function() {
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_h = []; _j = BALANCED_PAIRS;
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for (_i = 0, _k = _j.length; _i < _k; _i++) {
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pair = _j[_i];
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_h.push(pair[1]);
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}
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return _h;
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}).call(this);
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// Tokens that indicate the close of a clause of an expression.
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EXPRESSION_CLOSE = ['CATCH', 'WHEN', 'ELSE', 'FINALLY'].concat(EXPRESSION_END);
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// Tokens that, if followed by an `IMPLICIT_CALL`, indicate a function invocation.
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IMPLICIT_FUNC = ['IDENTIFIER', 'SUPER', ')', 'CALL_END', ']', 'INDEX_END', '<-'];
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// If preceded by an `IMPLICIT_FUNC`, indicates a function invocation.
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IMPLICIT_CALL = ['IDENTIFIER', 'NUMBER', 'STRING', 'JS', 'REGEX', 'NEW', 'PARAM_START', 'TRY', 'DELETE', 'TYPEOF', 'SWITCH', 'EXTENSION', 'TRUE', 'FALSE', 'YES', 'NO', 'ON', 'OFF', '!', '!!', 'NOT', 'THIS', 'NULL', '@', '->', '=>', '[', '(', '{'];
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// Tokens indicating that the implicit call must enclose a block of expressions.
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IMPLICIT_BLOCK = ['->', '=>', '{', '[', ','];
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// Tokens that always mark the end of an implicit call for single-liners.
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IMPLICIT_END = ['IF', 'UNLESS', 'FOR', 'WHILE', 'TERMINATOR', 'INDENT', 'OUTDENT'];
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// Single-line flavors of block expressions that have unclosed endings.
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// The grammar can't disambiguate them, so we insert the implicit indentation.
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SINGLE_LINERS = ['ELSE', "->", "=>", 'TRY', 'FINALLY', 'THEN'];
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SINGLE_CLOSERS = ['TERMINATOR', 'CATCH', 'FINALLY', 'ELSE', 'OUTDENT', 'LEADING_WHEN'];
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})();
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