| // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| // Utilities for building JS ASTs at runtime. Contains a builder class |
| // and a parser that parses part of the language. |
| |
| part of js_ast; |
| |
| |
| /** |
| * Global template manager. We should aim to have a fixed number of |
| * templates. This implies that we do not use js('xxx') to parse text that is |
| * constructed from values that depend on names in the Dart program. |
| * |
| * TODO(sra): Find the remaining places where js('xxx') used to parse an |
| * unbounded number of expression, or institute a cache policy. |
| */ |
| TemplateManager templateManager = new TemplateManager(); |
| |
| |
| /** |
| |
| [js] is a singleton instace of JsBuilder. JsBuilder is a set of conveniences |
| for constructing JavaScript ASTs. |
| |
| [string] and [number] are used to create leaf AST nodes: |
| |
| var s = js.string('hello'); // s = new LiteralString('"hello"') |
| var n = js.number(123); // n = new LiteralNumber(123) |
| |
| In the line above `a --> b` means Dart expression `a` evaluates to a JavaScript |
| AST that would pretty-print as `b`. |
| |
| The [call] method constructs an Expression AST. |
| |
| No argument |
| |
| js('window.alert("hello")') --> window.alert("hello") |
| |
| The input text can contain placeholders `#` that are replaced with provided |
| arguments. A single argument can be passed directly: |
| |
| js('window.alert(#)', s) --> window.alert("hello") |
| |
| Multiple arguments are passed as a list: |
| |
| js('# + #', [s, s]) --> "hello" + "hello" |
| |
| The [statement] method constructs a Statement AST, but is otherwise like the |
| [call] method. This constructs a Return AST: |
| |
| var ret = js.statement('return #;', n); --> return 123; |
| |
| A placeholder in a Statement context must be followed by a semicolon ';'. You |
| can think of a statement placeholder as being `#;` to explain why the output |
| still has one semicolon: |
| |
| js.statement('if (happy) #;', ret) |
| --> |
| if (happy) |
| return 123; |
| |
| If the placeholder is not followed by a semicolon, it is part of an expression. |
| Here the paceholder is in the position of the function in a function call: |
| |
| var vFoo = new VariableUse('foo'); |
| js.statement('if (happy) #("Happy!")', vFoo) |
| --> |
| if (happy) |
| foo("Happy!"); |
| |
| Generally, a placeholder in an expression position requires an Expression AST as |
| an argument and a placeholder in a statement position requires a Statement AST. |
| An expression will be converted to a Statement if needed by creating an |
| ExpessionStatement. A String argument will be converted into a VariableUse and |
| requires that the string is a JavaScript identifier. |
| |
| js('# + 1', vFoo) --> foo + 1 |
| js('# + 1', 'foo') --> foo + 1 |
| js('# + 1', 'foo.bar') --> assertion failure |
| |
| Some placeholder positions are _splicing contexts_. A function argument list is |
| a splicing expression context. A placeholder in a splicing expression context |
| can take a single Expression (or String, converted to VariableUse) or an |
| Iterable of Expressions (and/or Strings). |
| |
| // non-splicing argument: |
| js('#(#)', ['say', s]) --> say("hello") |
| // splicing arguments: |
| js('#(#)', ['say', []]) --> say() |
| js('#(#)', ['say', [s]]) --> say("hello") |
| js('#(#)', ['say', [s, n]]) --> say("hello", 123) |
| |
| A splicing context can be used to append 'lists' and add extra elements: |
| |
| js('foo(#, #, 1)', [ ['a', n], s]) --> foo(a, 123, "hello", 1) |
| js('foo(#, #, 1)', [ ['a', n], [s, n]]) --> foo(a, 123, "hello", 123, 1) |
| js('foo(#, #, 1)', [ [], [s, n]]) --> foo("hello", 123, 1) |
| js('foo(#, #, 1)', [ [], [] ]) --> foo(1) |
| |
| The generation of a compile-time optional argument expression can be chosen by |
| providing an empty or singleton list. |
| |
| In addition to Expressions and Statements, there are Parameters, which occur |
| only in the parameter list of a function expression or declaration. |
| Placeholders in parameter positions behave like placeholders in Expression |
| positions, except only Parameter AST nodes are permitted. String arguments for |
| parameter placeholders are converted to Parameter AST nodes. |
| |
| var pFoo = new Parameter('foo') |
| js('function(#) { return #; }', [pFoo, vFoo]) |
| --> |
| function(foo) { return foo; } |
| |
| Expressions and Parameters are not compatible with each other's context: |
| |
| js('function(#) { return #; }', [vFoo, vFoo]) --> error |
| js('function(#) { return #; }', [pFoo, pFoo]) --> error |
| |
| The parameter context is a splicing context. When combined with the |
| context-sensitive conversion of Strings, this simplifies the construction of |
| trampoline-like functions: |
| |
| var args = ['a', 'b']; |
| js('function(#) { return f(this, #); }', [args, args]) |
| --> |
| function(a, b) { return f(this, a, b); } |
| |
| A statement placeholder in a Block is also in a splicing context. In addition |
| to splicing Iterables, statement placeholders in a Block will also splice a |
| Block or an EmptyStatement. This flattens nested blocks and allows blocks to be |
| appended. |
| |
| var b1 = js.statement('{ 1; 2; }'); |
| var sEmpty = new Emptystatement(); |
| js.statement('{ #; #; #; #; }', [sEmpty, b1, b1, sEmpty]) |
| --> |
| { 1; 2; 1; 2; } |
| |
| A placeholder in the context of an if-statement condition also accepts a Dart |
| bool argument, which selects the then-part or else-part of the if-statement: |
| |
| js.statement('if (#) return;', vFoo) --> if (foo) return; |
| js.statement('if (#) return;', true) --> return; |
| js.statement('if (#) return;', false) --> ; // empty statement |
| var eTrue = new LiteralBool(true); |
| js.statement('if (#) return;', eTrue) --> if (true) return; |
| |
| Combined with block splicing, if-statement condition context placeholders allows |
| the creation of tenplates that select code depending on variables. |
| |
| js.statement('{ 1; if (#) 2; else { 3; 4; } 5;}', true) |
| --> { 1; 2; 5; } |
| |
| js.statement('{ 1; if (#) 2; else { 3; 4; } 5;}', false) |
| --> { 1; 3; 4; 5; } |
| |
| A placeholder following a period in a property access is in a property access |
| context. This is just like an expression context, except String arguments are |
| converted to JavaScript property accesses. In JavaScript, `a.b` is short-hand |
| for `a["b"]`: |
| |
| js('a[#]', vFoo) --> a[foo] |
| js('a[#]', s) --> a.hello (i.e. a["hello"]). |
| js('a[#]', 'x') --> a[x] |
| |
| js('a.#', vFoo) --> a[foo] |
| js('a.#', s) --> a.hello (i.e. a["hello"]) |
| js('a.#', 'x') --> a.x (i.e. a["x"]) |
| |
| (Question - should `.#` be restricted to permit only String arguments? The |
| template should probably be writted with `[]` if non-strings are accepted.) |
| |
| |
| Object initialiers allow placeholders in the key property name position: |
| |
| js('{#:1, #:2}', [s, 'bye']) --> {hello: 1, bye: 2} |
| |
| |
| What is not implemented: |
| |
| - Array initializers and object initializers could support splicing. In the |
| array case, we would need some way to know if an ArrayInitializer argument |
| should be splice or is intended as a single value. |
| |
| - There are no placeholders in definition contexts: |
| |
| function #(){} |
| var # = 1; |
| |
| */ |
| const JsBuilder js = const JsBuilder(); |
| |
| |
| class JsBuilder { |
| const JsBuilder(); |
| |
| /** |
| * Parses a bit of JavaScript, and returns an expression. |
| * |
| * See the MiniJsParser class. |
| * |
| * [arguments] can be a single [Node] (e.g. an [Expression] or [Statement]) or |
| * a list of [Node]s, which will be interpolated into the source at the '#' |
| * signs. |
| */ |
| Expression call(String source, [var arguments]) { |
| Template template = _findExpressionTemplate(source); |
| if (arguments == null) return template.instantiate([]); |
| // We allow a single argument to be given directly. |
| if (arguments is! List && arguments is! Map) arguments = [arguments]; |
| return template.instantiate(arguments); |
| } |
| |
| /** |
| * Parses a JavaScript Statement, otherwise just like [call]. |
| */ |
| Statement statement(String source, [var arguments]) { |
| Template template = _findStatementTemplate(source); |
| if (arguments == null) return template.instantiate([]); |
| // We allow a single argument to be given directly. |
| if (arguments is! List && arguments is! Map) arguments = [arguments]; |
| return template.instantiate(arguments); |
| } |
| |
| /** |
| * Parses JavaScript written in the `JS` foreign instruction. |
| * |
| * The [source] must be a JavaScript expression or a JavaScript throw |
| * statement. |
| */ |
| Template parseForeignJS(String source) { |
| // TODO(sra): Parse with extra validation to forbid `#` interpolation in |
| // functions, as this leads to unanticipated capture of temporaries that are |
| // reused after capture. |
| if (source.startsWith("throw ")) { |
| return _findStatementTemplate(source); |
| } else { |
| return _findExpressionTemplate(source); |
| } |
| } |
| |
| Template _findExpressionTemplate(String source) { |
| Template template = templateManager.lookupExpressionTemplate(source); |
| if (template == null) { |
| MiniJsParser parser = new MiniJsParser(source); |
| Expression expression = parser.expression(); |
| template = templateManager.defineExpressionTemplate(source, expression); |
| } |
| return template; |
| } |
| |
| Template _findStatementTemplate(String source) { |
| Template template = templateManager.lookupStatementTemplate(source); |
| if (template == null) { |
| MiniJsParser parser = new MiniJsParser(source); |
| Statement statement = parser.statement(); |
| template = templateManager.defineStatementTemplate(source, statement); |
| } |
| return template; |
| } |
| |
| /** |
| * Creates an Expression template without caching the result. |
| */ |
| Template uncachedExpressionTemplate(String source) { |
| MiniJsParser parser = new MiniJsParser(source); |
| Expression expression = parser.expression(); |
| return new Template( |
| source, expression, isExpression: true, forceCopy: false); |
| } |
| |
| /** |
| * Creates a Statement template without caching the result. |
| */ |
| Template uncachedStatementTemplate(String source) { |
| MiniJsParser parser = new MiniJsParser(source); |
| Statement statement = parser.statement(); |
| return new Template( |
| source, statement, isExpression: false, forceCopy: false); |
| } |
| |
| /** |
| * Create an Expression template which has [ast] as the result. This is used |
| * to wrap a generated AST in a zero-argument Template so it can be passed to |
| * context that expects a template. |
| */ |
| Template expressionTemplateYielding(Node ast) { |
| return new Template.withExpressionResult(ast); |
| } |
| |
| Template statementTemplateYielding(Node ast) { |
| return new Template.withStatementResult(ast); |
| } |
| |
| /// Creates a literal js string from [value]. |
| LiteralString escapedString(String value) { |
| // Start by escaping the backslashes. |
| String escaped = value.replaceAll('\\', '\\\\'); |
| // Do not escape unicode characters and ' because they are allowed in the |
| // string literal anyway. |
| escaped = escaped.replaceAllMapped(new RegExp('\n|"|\b|\t|\v'), (match) { |
| switch (match.group(0)) { |
| case "\n" : return r"\n"; |
| case "\"" : return r'\"'; |
| case "\b" : return r"\b"; |
| case "\t" : return r"\t"; |
| case "\f" : return r"\f"; |
| case "\v" : return r"\v"; |
| } |
| }); |
| LiteralString result = string(escaped); |
| // We don't escape ' under the assumption that the string is wrapped |
| // into ". Verify that assumption. |
| assert(result.value.codeUnitAt(0) == '"'.codeUnitAt(0)); |
| return result; |
| } |
| |
| /// Creates a literal js string from [value]. |
| /// |
| /// Note that this function only puts quotes around [value]. It does not do |
| /// any escaping, so use only when you can guarantee that [value] does not |
| /// contain newlines or backslashes. For escaping the string use |
| /// [escapedString]. |
| LiteralString string(String value) => new LiteralString('"$value"'); |
| |
| LiteralNumber number(num value) => new LiteralNumber('$value'); |
| |
| LiteralBool boolean(bool value) => new LiteralBool(value); |
| |
| ArrayInitializer numArray(Iterable<int> list) => |
| new ArrayInitializer(list.map(number).toList()); |
| |
| ArrayInitializer stringArray(Iterable<String> list) => |
| new ArrayInitializer(list.map(string).toList()); |
| |
| Comment comment(String text) => new Comment(text); |
| |
| Call propertyCall(Expression receiver, |
| String fieldName, |
| List<Expression> arguments) { |
| return new Call(new PropertyAccess.field(receiver, fieldName), arguments); |
| } |
| } |
| |
| LiteralString string(String value) => js.string(value); |
| LiteralNumber number(num value) => js.number(value); |
| ArrayInitializer numArray(Iterable<int> list) => js.numArray(list); |
| ArrayInitializer stringArray(Iterable<String> list) => js.stringArray(list); |
| Call propertyCall(Expression receiver, |
| String fieldName, |
| List<Expression> arguments) { |
| return js.propertyCall(receiver, fieldName, arguments); |
| } |
| |
| class MiniJsParserError { |
| MiniJsParserError(this.parser, this.message) { } |
| |
| final MiniJsParser parser; |
| final String message; |
| |
| String toString() { |
| int pos = parser.lastPosition; |
| |
| // Discard lines following the line containing lastPosition. |
| String src = parser.src; |
| int newlinePos = src.indexOf('\n', pos); |
| if (newlinePos >= pos) src = src.substring(0, newlinePos); |
| |
| // Extract the prefix of the error line before lastPosition. |
| String line = src; |
| int lastLineStart = line.lastIndexOf('\n'); |
| if (lastLineStart >= 0) line = line.substring(lastLineStart + 1); |
| String prefix = line.substring(0, pos - (src.length - line.length)); |
| |
| // Replace non-tabs with spaces, giving a print indent that matches the text |
| // for tabbing. |
| String spaces = prefix.replaceAll(new RegExp(r'[^\t]'), ' '); |
| return 'Error in MiniJsParser:\n${src}\n$spaces^\n$spaces$message\n'; |
| } |
| } |
| |
| /// Mini JavaScript parser for tiny snippets of code that we want to make into |
| /// AST nodes. Handles: |
| /// * identifiers. |
| /// * dot access. |
| /// * method calls. |
| /// * [] access. |
| /// * array, string, regexp, boolean, null and numeric literals. |
| /// * most operators. |
| /// * brackets. |
| /// * var declarations. |
| /// * operator precedence. |
| /// * anonymous funtions and named function expressions and declarations. |
| /// Notable things it can't do yet include: |
| /// * some statements are still missing (do-while, while, switch). |
| /// |
| /// It's a fairly standard recursive descent parser. |
| /// |
| /// Literal strings are passed through to the final JS source code unchanged, |
| /// including the choice of surrounding quotes, so if you parse |
| /// r'var x = "foo\n\"bar\""' you will end up with |
| /// var x = "foo\n\"bar\"" in the final program. \x and \u escapes are not |
| /// allowed in string and regexp literals because the machinery for checking |
| /// their correctness is rather involved. |
| class MiniJsParser { |
| MiniJsParser(this.src) |
| : lastCategory = NONE, |
| lastToken = null, |
| lastPosition = 0, |
| position = 0 { |
| getToken(); |
| } |
| |
| int lastCategory = NONE; |
| String lastToken = null; |
| int lastPosition = 0; |
| int position = 0; |
| bool skippedNewline = false; // skipped newline in last getToken? |
| final String src; |
| |
| final List<InterpolatedNode> interpolatedValues = <InterpolatedNode>[]; |
| bool get hasNamedHoles => |
| interpolatedValues.isNotEmpty && interpolatedValues.first.isNamed; |
| bool get hasPositionalHoles => |
| interpolatedValues.isNotEmpty && interpolatedValues.first.isPositional; |
| |
| static const NONE = -1; |
| static const ALPHA = 0; |
| static const NUMERIC = 1; |
| static const STRING = 2; |
| static const SYMBOL = 3; |
| static const ASSIGNMENT = 4; |
| static const DOT = 5; |
| static const LPAREN = 6; |
| static const RPAREN = 7; |
| static const LBRACE = 8; |
| static const RBRACE = 9; |
| static const LSQUARE = 10; |
| static const RSQUARE = 11; |
| static const COMMA = 12; |
| static const QUERY = 13; |
| static const COLON = 14; |
| static const SEMICOLON = 15; |
| static const HASH = 16; |
| static const WHITESPACE = 17; |
| static const OTHER = 18; |
| |
| // Make sure that ]] is two symbols. |
| bool singleCharCategory(int category) => category >= DOT; |
| |
| static String categoryToString(int cat) { |
| switch (cat) { |
| case NONE: return "NONE"; |
| case ALPHA: return "ALPHA"; |
| case NUMERIC: return "NUMERIC"; |
| case SYMBOL: return "SYMBOL"; |
| case ASSIGNMENT: return "ASSIGNMENT"; |
| case DOT: return "DOT"; |
| case LPAREN: return "LPAREN"; |
| case RPAREN: return "RPAREN"; |
| case LBRACE: return "LBRACE"; |
| case RBRACE: return "RBRACE"; |
| case LSQUARE: return "LSQUARE"; |
| case RSQUARE: return "RSQUARE"; |
| case STRING: return "STRING"; |
| case COMMA: return "COMMA"; |
| case QUERY: return "QUERY"; |
| case COLON: return "COLON"; |
| case SEMICOLON: return "SEMICOLON"; |
| case HASH: return "HASH"; |
| case WHITESPACE: return "WHITESPACE"; |
| case OTHER: return "OTHER"; |
| } |
| return "Unknown: $cat"; |
| } |
| |
| static const CATEGORIES = const <int>[ |
| OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, // 0-7 |
| OTHER, WHITESPACE, WHITESPACE, OTHER, OTHER, WHITESPACE, // 8-13 |
| OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, // 14-21 |
| OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, OTHER, // 22-29 |
| OTHER, OTHER, WHITESPACE, // 30-32 |
| SYMBOL, OTHER, HASH, ALPHA, SYMBOL, SYMBOL, OTHER, // !"#$%&´ |
| LPAREN, RPAREN, SYMBOL, SYMBOL, COMMA, SYMBOL, DOT, SYMBOL, // ()*+,-./ |
| NUMERIC, NUMERIC, NUMERIC, NUMERIC, NUMERIC, // 01234 |
| NUMERIC, NUMERIC, NUMERIC, NUMERIC, NUMERIC, // 56789 |
| COLON, SEMICOLON, SYMBOL, SYMBOL, SYMBOL, QUERY, OTHER, // :;<=>?@ |
| ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, // ABCDEFGH |
| ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, // IJKLMNOP |
| ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, // QRSTUVWX |
| ALPHA, ALPHA, LSQUARE, OTHER, RSQUARE, SYMBOL, ALPHA, OTHER, // YZ[\]^_' |
| ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, // abcdefgh |
| ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, // ijklmnop |
| ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, ALPHA, // qrstuvwx |
| ALPHA, ALPHA, LBRACE, SYMBOL, RBRACE, SYMBOL]; // yz{|}~ |
| |
| // This must be a >= the highest precedence number handled by parseBinary. |
| static var HIGHEST_PARSE_BINARY_PRECEDENCE = 16; |
| static bool isAssignment(String symbol) => BINARY_PRECEDENCE[symbol] == 17; |
| |
| // From https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Operators/Operator_Precedence |
| static final BINARY_PRECEDENCE = { |
| '+=': 17, '-=': 17, '*=': 17, '/=': 17, '%=': 17, '^=': 17, '|=': 17, |
| '&=': 17, '<<=': 17, '>>=': 17, '>>>=': 17, '=': 17, |
| '||': 14, |
| '&&': 13, |
| '|': 12, |
| '^': 11, |
| '&': 10, |
| '!=': 9, '==': 9, '!==': 9, '===': 9, |
| '<': 8, '<=': 8, '>=': 8, '>': 8, 'in': 8, 'instanceof': 8, |
| '<<': 7, '>>': 7, '>>>': 7, |
| '+': 6, '-': 6, |
| '*': 5, '/': 5, '%': 5 |
| }; |
| static final UNARY_OPERATORS = |
| ['++', '--', '+', '-', '~', '!', 'typeof', 'void', 'delete', 'await'] |
| .toSet(); |
| |
| static final OPERATORS_THAT_LOOK_LIKE_IDENTIFIERS = |
| ['typeof', 'void', 'delete', 'in', 'instanceof', 'await'].toSet(); |
| |
| static int category(int code) { |
| if (code >= CATEGORIES.length) return OTHER; |
| return CATEGORIES[code]; |
| } |
| |
| String getDelimited(int startPosition) { |
| position = startPosition; |
| int delimiter = src.codeUnitAt(startPosition); |
| int currentCode; |
| do { |
| position++; |
| if (position >= src.length) error("Unterminated literal"); |
| currentCode = src.codeUnitAt(position); |
| if (currentCode == charCodes.$LF) error("Unterminated literal"); |
| if (currentCode == charCodes.$BACKSLASH) { |
| if (++position >= src.length) error("Unterminated literal"); |
| int escaped = src.codeUnitAt(position); |
| if (escaped == charCodes.$x || escaped == charCodes.$X || |
| escaped == charCodes.$u || escaped == charCodes.$U || |
| category(escaped) == NUMERIC) { |
| error('Numeric and hex escapes are not allowed in literals'); |
| } |
| } |
| } while (currentCode != delimiter); |
| position++; |
| return src.substring(lastPosition, position); |
| } |
| |
| void getToken() { |
| skippedNewline = false; |
| for (;;) { |
| if (position >= src.length) break; |
| int code = src.codeUnitAt(position); |
| // Skip '//' and '/*' style comments. |
| if (code == charCodes.$SLASH && |
| position + 1 < src.length) { |
| if (src.codeUnitAt(position + 1) == charCodes.$SLASH) { |
| int nextPosition = src.indexOf('\n', position); |
| if (nextPosition == -1) nextPosition = src.length; |
| position = nextPosition; |
| continue; |
| } else if (src.codeUnitAt(position + 1) == charCodes.$STAR) { |
| int nextPosition = src.indexOf('*/', position + 2); |
| if (nextPosition == -1) error('Unterminated comment'); |
| position = nextPosition + 2; |
| continue; |
| } |
| } |
| if (category(code) != WHITESPACE) break; |
| if (code == charCodes.$LF) skippedNewline = true; |
| ++position; |
| } |
| |
| if (position == src.length) { |
| lastCategory = NONE; |
| lastToken = null; |
| lastPosition = position; |
| return; |
| } |
| int code = src.codeUnitAt(position); |
| lastPosition = position; |
| if (code == charCodes.$SQ || code == charCodes.$DQ) { |
| // String literal. |
| lastCategory = STRING; |
| lastToken = getDelimited(position); |
| } else if (code == charCodes.$0 && |
| position + 2 < src.length && |
| src.codeUnitAt(position + 1) == charCodes.$x) { |
| // Hex literal. |
| for (position += 2; position < src.length; position++) { |
| int cat = category(src.codeUnitAt(position)); |
| if (cat != NUMERIC && cat != ALPHA) break; |
| } |
| lastCategory = NUMERIC; |
| lastToken = src.substring(lastPosition, position); |
| int.parse(lastToken, onError: (_) { |
| error("Unparseable number"); |
| }); |
| } else if (code == charCodes.$SLASH) { |
| // Tokens that start with / are special due to regexp literals. |
| lastCategory = SYMBOL; |
| position++; |
| if (position < src.length && src.codeUnitAt(position) == charCodes.$EQ) { |
| position++; |
| } |
| lastToken = src.substring(lastPosition, position); |
| } else { |
| // All other tokens handled here. |
| int cat = category(src.codeUnitAt(position)); |
| int newCat; |
| do { |
| position++; |
| if (position == src.length) break; |
| int code = src.codeUnitAt(position); |
| // Special code to disallow ! and / in non-first position in token, so |
| // that !! parses as two tokens and != parses as one, while =/ parses |
| // as a an equals token followed by a regexp literal start. |
| newCat = (code == charCodes.$BANG || code == charCodes.$SLASH) |
| ? NONE |
| : category(code); |
| } while (!singleCharCategory(cat) && |
| (cat == newCat || |
| (cat == ALPHA && newCat == NUMERIC) || // eg. level42. |
| (cat == NUMERIC && newCat == DOT))); // eg. 3.1415 |
| lastCategory = cat; |
| lastToken = src.substring(lastPosition, position); |
| if (cat == NUMERIC) { |
| double.parse(lastToken, (_) { |
| error("Unparseable number"); |
| }); |
| } else if (cat == SYMBOL) { |
| int binaryPrecendence = BINARY_PRECEDENCE[lastToken]; |
| if (binaryPrecendence == null && !UNARY_OPERATORS.contains(lastToken)) { |
| error("Unknown operator"); |
| } |
| if (isAssignment(lastToken)) lastCategory = ASSIGNMENT; |
| } else if (cat == ALPHA) { |
| if (OPERATORS_THAT_LOOK_LIKE_IDENTIFIERS.contains(lastToken)) { |
| lastCategory = SYMBOL; |
| } |
| } |
| } |
| } |
| |
| void expectCategory(int cat) { |
| if (cat != lastCategory) error("Expected ${categoryToString(cat)}"); |
| getToken(); |
| } |
| |
| bool acceptCategory(int cat) { |
| if (cat == lastCategory) { |
| getToken(); |
| return true; |
| } |
| return false; |
| } |
| |
| void expectSemicolon() { |
| if (acceptSemicolon()) return; |
| error('Expected SEMICOLON'); |
| } |
| |
| bool acceptSemicolon() { |
| // Accept semicolon or automatically inserted semicolon before close brace. |
| // Miniparser forbids other kinds of semicolon insertion. |
| if (RBRACE == lastCategory) return true; |
| if (NONE == lastCategory) return true; // end of input |
| if (skippedNewline) { |
| error('No automatic semicolon insertion at preceding newline'); |
| } |
| return acceptCategory(SEMICOLON); |
| } |
| |
| bool acceptString(String string) { |
| if (lastToken == string) { |
| getToken(); |
| return true; |
| } |
| return false; |
| } |
| |
| void error(message) { |
| throw new MiniJsParserError(this, message); |
| } |
| |
| /// Returns either the name for the hole, or its integer position. |
| parseHash() { |
| String holeName = lastToken; |
| if (acceptCategory(ALPHA)) { |
| // Named hole. Example: 'function #funName() { ... }' |
| if (hasPositionalHoles) { |
| error('Holes must all be positional or named. $holeName'); |
| } |
| return holeName; |
| } else { |
| if (hasNamedHoles) { |
| error('Holes must all be positional or named. $holeName'); |
| } |
| int position = interpolatedValues.length; |
| return position; |
| } |
| } |
| |
| Expression parsePrimary() { |
| String last = lastToken; |
| if (acceptCategory(ALPHA)) { |
| if (last == "true") { |
| return new LiteralBool(true); |
| } else if (last == "false") { |
| return new LiteralBool(false); |
| } else if (last == "null") { |
| return new LiteralNull(); |
| } else if (last == "function") { |
| return parseFunctionExpression(); |
| } else if (last == "this") { |
| return new This(); |
| } else { |
| return new VariableUse(last); |
| } |
| } else if (acceptCategory(LPAREN)) { |
| Expression expression = parseExpression(); |
| expectCategory(RPAREN); |
| return expression; |
| } else if (acceptCategory(STRING)) { |
| return new LiteralString(last); |
| } else if (acceptCategory(NUMERIC)) { |
| return new LiteralNumber(last); |
| } else if (acceptCategory(LBRACE)) { |
| return parseObjectInitializer(); |
| } else if (acceptCategory(LSQUARE)) { |
| var values = <Expression>[]; |
| |
| while (true) { |
| if (acceptCategory(COMMA)) { |
| values.add(new ArrayHole()); |
| continue; |
| } |
| if (acceptCategory(RSQUARE)) break; |
| values.add(parseAssignment()); |
| if (acceptCategory(RSQUARE)) break; |
| expectCategory(COMMA); |
| } |
| return new ArrayInitializer(values); |
| } else if (last != null && last.startsWith("/")) { |
| String regexp = getDelimited(lastPosition); |
| getToken(); |
| String flags = lastToken; |
| if (!acceptCategory(ALPHA)) flags = ""; |
| Expression expression = new RegExpLiteral(regexp + flags); |
| return expression; |
| } else if (acceptCategory(HASH)) { |
| var nameOrPosition = parseHash(); |
| InterpolatedExpression expression = |
| new InterpolatedExpression(nameOrPosition); |
| interpolatedValues.add(expression); |
| return expression; |
| } else { |
| error("Expected primary expression"); |
| return null; |
| } |
| } |
| |
| Expression parseFunctionExpression() { |
| String last = lastToken; |
| if (acceptCategory(ALPHA)) { |
| String functionName = last; |
| return new NamedFunction(new VariableDeclaration(functionName), |
| parseFun()); |
| } |
| return parseFun(); |
| } |
| |
| Expression parseFun() { |
| List<Parameter> params = <Parameter>[]; |
| |
| expectCategory(LPAREN); |
| if (!acceptCategory(RPAREN)) { |
| for (;;) { |
| if (acceptCategory(HASH)) { |
| var nameOrPosition = parseHash(); |
| InterpolatedParameter parameter = |
| new InterpolatedParameter(nameOrPosition); |
| interpolatedValues.add(parameter); |
| params.add(parameter); |
| } else { |
| String argumentName = lastToken; |
| expectCategory(ALPHA); |
| params.add(new Parameter(argumentName)); |
| } |
| if (acceptCategory(COMMA)) continue; |
| expectCategory(RPAREN); |
| break; |
| } |
| } |
| AsyncModifier asyncModifier; |
| if (acceptString('async')) { |
| if (acceptString('*')) { |
| asyncModifier = const AsyncModifier.asyncStar(); |
| } else { |
| asyncModifier = const AsyncModifier.async(); |
| } |
| } else if (acceptString('sync')) { |
| if (!acceptString('*')) error("Only sync* is valid - sync is implied"); |
| asyncModifier = const AsyncModifier.syncStar(); |
| } else { |
| asyncModifier = const AsyncModifier.sync(); |
| } |
| expectCategory(LBRACE); |
| Block block = parseBlock(); |
| return new Fun(params, block, asyncModifier: asyncModifier); |
| } |
| |
| Expression parseObjectInitializer() { |
| List<Property> properties = <Property>[]; |
| for (;;) { |
| if (acceptCategory(RBRACE)) break; |
| // Limited subset: keys are identifiers, no 'get' or 'set' properties. |
| Literal propertyName; |
| String identifier = lastToken; |
| if (acceptCategory(ALPHA)) { |
| propertyName = new LiteralString('"$identifier"'); |
| } else if (acceptCategory(STRING)) { |
| propertyName = new LiteralString(identifier); |
| } else if (acceptCategory(SYMBOL)) { // e.g. void |
| propertyName = new LiteralString('"$identifier"'); |
| } else if (acceptCategory(HASH)) { |
| var nameOrPosition = parseHash(); |
| InterpolatedLiteral interpolatedLiteral = |
| new InterpolatedLiteral(nameOrPosition); |
| interpolatedValues.add(interpolatedLiteral); |
| propertyName = interpolatedLiteral; |
| } else { |
| error('Expected property name'); |
| } |
| expectCategory(COLON); |
| Expression value = parseAssignment(); |
| properties.add(new Property(propertyName, value)); |
| if (acceptCategory(RBRACE)) break; |
| expectCategory(COMMA); |
| } |
| return new ObjectInitializer(properties); |
| } |
| |
| Expression parseMember() { |
| Expression receiver = parsePrimary(); |
| while (true) { |
| if (acceptCategory(DOT)) { |
| receiver = getDotRhs(receiver); |
| } else if (acceptCategory(LSQUARE)) { |
| Expression inBraces = parseExpression(); |
| expectCategory(RSQUARE); |
| receiver = new PropertyAccess(receiver, inBraces); |
| } else { |
| break; |
| } |
| } |
| return receiver; |
| } |
| |
| Expression parseCall() { |
| bool constructor = acceptString("new"); |
| Expression receiver = parseMember(); |
| while (true) { |
| if (acceptCategory(LPAREN)) { |
| final arguments = <Expression>[]; |
| if (!acceptCategory(RPAREN)) { |
| while (true) { |
| Expression argument = parseAssignment(); |
| arguments.add(argument); |
| if (acceptCategory(RPAREN)) break; |
| expectCategory(COMMA); |
| } |
| } |
| receiver = constructor ? |
| new New(receiver, arguments) : |
| new Call(receiver, arguments); |
| constructor = false; |
| } else if (!constructor && acceptCategory(LSQUARE)) { |
| Expression inBraces = parseExpression(); |
| expectCategory(RSQUARE); |
| receiver = new PropertyAccess(receiver, inBraces); |
| } else if (!constructor && acceptCategory(DOT)) { |
| receiver = getDotRhs(receiver); |
| } else { |
| // JS allows new without (), but we don't. |
| if (constructor) error("Parentheses are required for new"); |
| break; |
| } |
| } |
| return receiver; |
| } |
| |
| Expression getDotRhs(Expression receiver) { |
| if (acceptCategory(HASH)) { |
| var nameOrPosition = parseHash(); |
| InterpolatedSelector property = new InterpolatedSelector(nameOrPosition); |
| interpolatedValues.add(property); |
| return new PropertyAccess(receiver, property); |
| } |
| String identifier = lastToken; |
| // In ES5 keywords like delete and continue are allowed as property |
| // names, and the IndexedDB API uses that, so we need to allow it here. |
| if (acceptCategory(SYMBOL)) { |
| if (!OPERATORS_THAT_LOOK_LIKE_IDENTIFIERS.contains(identifier)) { |
| error("Expected alphanumeric identifier"); |
| } |
| } else { |
| expectCategory(ALPHA); |
| } |
| return new PropertyAccess.field(receiver, identifier); |
| } |
| |
| Expression parsePostfix() { |
| Expression expression = parseCall(); |
| String operator = lastToken; |
| // JavaScript grammar is: |
| // LeftHandSideExpression [no LineTerminator here] ++ |
| if (lastCategory == SYMBOL && |
| !skippedNewline && |
| (acceptString("++") || acceptString("--"))) { |
| return new Postfix(operator, expression); |
| } |
| // If we don't accept '++' or '--' due to skippedNewline a newline, no other |
| // part of the parser will accept the token and we will get an error at the |
| // whole expression level. |
| return expression; |
| } |
| |
| Expression parseUnaryHigh() { |
| String operator = lastToken; |
| if (lastCategory == SYMBOL && UNARY_OPERATORS.contains(operator) && |
| (acceptString("++") || acceptString("--") || acceptString('await'))) { |
| if (operator == "await") return new Await(parsePostfix()); |
| return new Prefix(operator, parsePostfix()); |
| } |
| return parsePostfix(); |
| } |
| |
| Expression parseUnaryLow() { |
| String operator = lastToken; |
| if (lastCategory == SYMBOL && UNARY_OPERATORS.contains(operator) && |
| operator != "++" && operator != "--") { |
| expectCategory(SYMBOL); |
| if (operator == "await") return new Await(parsePostfix()); |
| return new Prefix(operator, parseUnaryLow()); |
| } |
| return parseUnaryHigh(); |
| } |
| |
| Expression parseBinary(int maxPrecedence) { |
| Expression lhs = parseUnaryLow(); |
| int minPrecedence; |
| String lastSymbol; |
| Expression rhs; // This is null first time around. |
| while (true) { |
| String symbol = lastToken; |
| if (lastCategory != SYMBOL || |
| !BINARY_PRECEDENCE.containsKey(symbol) || |
| BINARY_PRECEDENCE[symbol] > maxPrecedence) { |
| break; |
| } |
| expectCategory(SYMBOL); |
| if (rhs == null || BINARY_PRECEDENCE[symbol] >= minPrecedence) { |
| if (rhs != null) lhs = new Binary(lastSymbol, lhs, rhs); |
| minPrecedence = BINARY_PRECEDENCE[symbol]; |
| rhs = parseUnaryLow(); |
| lastSymbol = symbol; |
| } else { |
| Expression higher = parseBinary(BINARY_PRECEDENCE[symbol]); |
| rhs = new Binary(symbol, rhs, higher); |
| } |
| } |
| if (rhs == null) return lhs; |
| return new Binary(lastSymbol, lhs, rhs); |
| } |
| |
| Expression parseConditional() { |
| Expression lhs = parseBinary(HIGHEST_PARSE_BINARY_PRECEDENCE); |
| if (!acceptCategory(QUERY)) return lhs; |
| Expression ifTrue = parseAssignment(); |
| expectCategory(COLON); |
| Expression ifFalse = parseAssignment(); |
| return new Conditional(lhs, ifTrue, ifFalse); |
| } |
| |
| |
| Expression parseAssignment() { |
| Expression lhs = parseConditional(); |
| String assignmentOperator = lastToken; |
| if (acceptCategory(ASSIGNMENT)) { |
| Expression rhs = parseAssignment(); |
| if (assignmentOperator == "=") { |
| return new Assignment(lhs, rhs); |
| } else { |
| // Handle +=, -=, etc. |
| String operator = |
| assignmentOperator.substring(0, assignmentOperator.length - 1); |
| return new Assignment.compound(lhs, operator, rhs); |
| } |
| } |
| return lhs; |
| } |
| |
| Expression parseExpression() { |
| Expression expression = parseAssignment(); |
| while (acceptCategory(COMMA)) { |
| Expression right = parseAssignment(); |
| expression = new Binary(',', expression, right); |
| } |
| return expression; |
| } |
| |
| VariableDeclarationList parseVariableDeclarationList() { |
| String firstVariable = lastToken; |
| expectCategory(ALPHA); |
| return finishVariableDeclarationList(firstVariable); |
| } |
| |
| VariableDeclarationList finishVariableDeclarationList(String firstVariable) { |
| var initialization = []; |
| |
| void declare(String variable) { |
| Expression initializer = null; |
| if (acceptString("=")) { |
| initializer = parseAssignment(); |
| } |
| var declaration = new VariableDeclaration(variable); |
| initialization.add(new VariableInitialization(declaration, initializer)); |
| } |
| |
| declare(firstVariable); |
| while (acceptCategory(COMMA)) { |
| String variable = lastToken; |
| expectCategory(ALPHA); |
| declare(variable); |
| } |
| return new VariableDeclarationList(initialization); |
| } |
| |
| Expression parseVarDeclarationOrExpression() { |
| if (acceptString("var")) { |
| return parseVariableDeclarationList(); |
| } else { |
| return parseExpression(); |
| } |
| } |
| |
| Expression expression() { |
| Expression expression = parseVarDeclarationOrExpression(); |
| if (lastCategory != NONE || position != src.length) { |
| error("Unparsed junk: ${categoryToString(lastCategory)}"); |
| } |
| return expression; |
| } |
| |
| Statement statement() { |
| Statement statement = parseStatement(); |
| if (lastCategory != NONE || position != src.length) { |
| error("Unparsed junk: ${categoryToString(lastCategory)}"); |
| } |
| // TODO(sra): interpolated capture here? |
| return statement; |
| } |
| |
| Block parseBlock() { |
| List<Statement> statements = <Statement>[]; |
| |
| while (!acceptCategory(RBRACE)) { |
| Statement statement = parseStatement(); |
| statements.add(statement); |
| } |
| return new Block(statements); |
| } |
| |
| Statement parseStatement() { |
| if (acceptCategory(LBRACE)) return parseBlock(); |
| |
| if (acceptCategory(SEMICOLON)) return new EmptyStatement(); |
| |
| if (lastCategory == ALPHA) { |
| if (acceptString('return')) return parseReturn(); |
| |
| if (acceptString('throw')) return parseThrow(); |
| |
| if (acceptString('break')) { |
| return parseBreakOrContinue((label) => new Break(label)); |
| } |
| |
| if (acceptString('continue')) { |
| return parseBreakOrContinue((label) => new Continue(label)); |
| } |
| |
| if (acceptString('if')) return parseIfThenElse(); |
| |
| if (acceptString('for')) return parseFor(); |
| |
| if (acceptString('function')) return parseFunctionDeclaration(); |
| |
| if (acceptString('try')) return parseTry(); |
| |
| if (acceptString('var')) { |
| Expression declarations = parseVariableDeclarationList(); |
| expectSemicolon(); |
| return new ExpressionStatement(declarations); |
| } |
| |
| if (acceptString('while')) return parseWhile(); |
| |
| if (acceptString('do')) return parseDo(); |
| |
| if (acceptString('switch')) return parseSwitch(); |
| |
| if (lastToken == 'case') error("Case outside switch."); |
| |
| if (lastToken == 'default') error("Default outside switch."); |
| |
| if (lastToken == 'yield') return parseYield(); |
| |
| if (lastToken == 'with') { |
| error('Not implemented in mini parser'); |
| } |
| |
| } |
| |
| bool checkForInterpolatedStatement = lastCategory == HASH; |
| |
| Expression expression = parseExpression(); |
| |
| if (expression is VariableUse && acceptCategory(COLON)) { |
| return new LabeledStatement(expression.name, parseStatement()); |
| } |
| |
| expectSemicolon(); |
| |
| if (checkForInterpolatedStatement) { |
| // 'Promote' the interpolated expression `#;` to an interpolated |
| // statement. |
| if (expression is InterpolatedExpression) { |
| assert(identical(interpolatedValues.last, expression)); |
| InterpolatedStatement statement = |
| new InterpolatedStatement(expression.nameOrPosition); |
| interpolatedValues[interpolatedValues.length - 1] = statement; |
| return statement; |
| } |
| } |
| |
| return new ExpressionStatement(expression); |
| } |
| |
| Statement parseReturn() { |
| if (acceptSemicolon()) return new Return(); |
| Expression expression = parseExpression(); |
| expectSemicolon(); |
| return new Return(expression); |
| } |
| |
| Statement parseYield() { |
| bool hasStar = acceptString('*'); |
| Expression expression = parseExpression(); |
| expectSemicolon(); |
| return new DartYield(expression, hasStar); |
| } |
| |
| Statement parseThrow() { |
| if (skippedNewline) error('throw expression must be on same line'); |
| Expression expression = parseExpression(); |
| expectSemicolon(); |
| return new Throw(expression); |
| } |
| |
| Statement parseBreakOrContinue(constructor) { |
| var identifier = lastToken; |
| if (!skippedNewline && acceptCategory(ALPHA)) { |
| expectSemicolon(); |
| return constructor(identifier); |
| } |
| expectSemicolon(); |
| return constructor(null); |
| } |
| |
| Statement parseIfThenElse() { |
| expectCategory(LPAREN); |
| Expression condition = parseExpression(); |
| expectCategory(RPAREN); |
| Statement thenStatement = parseStatement(); |
| if (acceptString('else')) { |
| // Resolves dangling else by binding 'else' to closest 'if'. |
| Statement elseStatement = parseStatement(); |
| return new If(condition, thenStatement, elseStatement); |
| } else { |
| return new If.noElse(condition, thenStatement); |
| } |
| } |
| |
| Statement parseFor() { |
| // For-init-condition-increment style loops are fully supported. |
| // |
| // Only one for-in variant is currently implemented: |
| // |
| // for (var variable in Expression) Statement |
| // |
| Statement finishFor(Expression init) { |
| Expression condition = null; |
| if (!acceptCategory(SEMICOLON)) { |
| condition = parseExpression(); |
| expectCategory(SEMICOLON); |
| } |
| Expression update = null; |
| if (!acceptCategory(RPAREN)) { |
| update = parseExpression(); |
| expectCategory(RPAREN); |
| } |
| Statement body = parseStatement(); |
| return new For(init, condition, update, body); |
| } |
| |
| expectCategory(LPAREN); |
| if (acceptCategory(SEMICOLON)) { |
| return finishFor(null); |
| } |
| |
| if (acceptString('var')) { |
| String identifier = lastToken; |
| expectCategory(ALPHA); |
| if (acceptString('in')) { |
| Expression objectExpression = parseExpression(); |
| expectCategory(RPAREN); |
| Statement body = parseStatement(); |
| return new ForIn( |
| new VariableDeclarationList([ |
| new VariableInitialization( |
| new VariableDeclaration(identifier), null)]), |
| objectExpression, |
| body); |
| } |
| Expression declarations = finishVariableDeclarationList(identifier); |
| expectCategory(SEMICOLON); |
| return finishFor(declarations); |
| } |
| |
| Expression init = parseExpression(); |
| expectCategory(SEMICOLON); |
| return finishFor(init); |
| } |
| |
| Statement parseFunctionDeclaration() { |
| String name = lastToken; |
| expectCategory(ALPHA); |
| Expression fun = parseFun(); |
| return new FunctionDeclaration(new VariableDeclaration(name), fun); |
| } |
| |
| Statement parseTry() { |
| expectCategory(LBRACE); |
| Block body = parseBlock(); |
| String token = lastToken; |
| Catch catchPart = null; |
| if (acceptString('catch')) catchPart = parseCatch(); |
| Block finallyPart = null; |
| if (acceptString('finally')) { |
| expectCategory(LBRACE); |
| finallyPart = parseBlock(); |
| } else { |
| if (catchPart == null) error("expected 'finally'"); |
| } |
| return new Try(body, catchPart, finallyPart); |
| } |
| |
| SwitchClause parseSwitchClause() { |
| Expression expression = null; |
| if (acceptString('case')) { |
| expression = parseExpression(); |
| expectCategory(COLON); |
| } else { |
| if (!acceptString('default')) { |
| error('expected case or default'); |
| } |
| expectCategory(COLON); |
| } |
| List statements = new List<Statement>(); |
| while (lastCategory != RBRACE && |
| lastToken != 'case' && |
| lastToken != 'default') { |
| statements.add(parseStatement()); |
| } |
| return expression == null |
| ? new Default(new Block(statements)) |
| : new Case(expression, new Block(statements)); |
| } |
| |
| Statement parseWhile() { |
| expectCategory(LPAREN); |
| Expression condition = parseExpression(); |
| expectCategory(RPAREN); |
| Statement body = parseStatement(); |
| return new While(condition, body); |
| } |
| |
| Statement parseDo() { |
| Statement body = parseStatement(); |
| if (lastToken != "while") error("Missing while after do body."); |
| getToken(); |
| expectCategory(LPAREN); |
| Expression condition = parseExpression(); |
| expectCategory(RPAREN); |
| expectSemicolon(); |
| return new Do(body, condition); |
| } |
| |
| Statement parseSwitch() { |
| expectCategory(LPAREN); |
| Expression key = parseExpression(); |
| expectCategory(RPAREN); |
| expectCategory(LBRACE); |
| List<SwitchClause> clauses = new List<SwitchClause>(); |
| while(lastCategory != RBRACE) { |
| clauses.add(parseSwitchClause()); |
| } |
| expectCategory(RBRACE); |
| return new Switch(key, clauses); |
| } |
| |
| Catch parseCatch() { |
| expectCategory(LPAREN); |
| String identifier = lastToken; |
| expectCategory(ALPHA); |
| expectCategory(RPAREN); |
| expectCategory(LBRACE); |
| Block body = parseBlock(); |
| return new Catch(new VariableDeclaration(identifier), body); |
| } |
| } |
