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3402 lines (2940 loc) · 127 KB
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/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Apache License, Version 2.0. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Apache License, Version 2.0, please send an email to
* [email protected]. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Apache License, Version 2.0.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using Microsoft.Scripting;
using Microsoft.Scripting.Runtime;
using Microsoft.Scripting.Utils;
using IronPython.Compiler.Ast;
using IronPython.Hosting;
using IronPython.Runtime;
using IronPython.Runtime.Exceptions;
using IronPython.Runtime.Types;
#if FEATURE_NUMERICS
using System.Numerics;
#else
using Microsoft.Scripting.Math;
#endif
namespace IronPython.Compiler {
public class Parser : IDisposable { // TODO: remove IDisposable
// immutable properties:
private readonly Tokenizer _tokenizer;
// mutable properties:
private ErrorSink _errors;
private ParserSink _sink;
// resettable properties:
private SourceUnit _sourceUnit;
/// <summary>
/// Language features initialized on parser construction and possibly updated during parsing.
/// The code can set the language features (e.g. "from __future__ import division").
/// </summary>
private ModuleOptions _languageFeatures;
// state:
private TokenWithSpan _token;
private TokenWithSpan _lookahead;
private Stack<FunctionDefinition> _functions;
private bool _fromFutureAllowed;
private string _privatePrefix;
private bool _parsingStarted, _allowIncomplete;
private bool _inLoop, _inFinally, _inFinallyLoop, _isGenerator, _returnWithValue;
private SourceCodeReader _sourceReader;
private int _errorCode;
private readonly CompilerContext _context;
private PythonAst _globalParent;
private static readonly char[] newLineChar = new char[] { '\n' };
private static readonly char[] whiteSpace = { ' ', '\t' };
#region Construction
private Parser(CompilerContext context, Tokenizer tokenizer, ErrorSink errorSink, ParserSink parserSink, ModuleOptions languageFeatures) {
ContractUtils.RequiresNotNull(tokenizer, "tokenizer");
ContractUtils.RequiresNotNull(errorSink, "errorSink");
ContractUtils.RequiresNotNull(parserSink, "parserSink");
tokenizer.ErrorSink = new TokenizerErrorSink(this);
_tokenizer = tokenizer;
_errors = errorSink;
if (parserSink != ParserSink.Null) {
_sink = parserSink;
}
_context = context;
Reset(tokenizer.SourceUnit, languageFeatures);
}
public static Parser CreateParser(CompilerContext context, PythonOptions options) {
return CreateParserWorker(context, options, false);
}
[Obsolete("pass verbatim via PythonCompilerOptions in PythonOptions")]
public static Parser CreateParser(CompilerContext context, PythonOptions options, bool verbatim) {
return CreateParserWorker(context, options, verbatim);
}
private static Parser CreateParserWorker(CompilerContext context, PythonOptions options, bool verbatim) {
ContractUtils.RequiresNotNull(context, "context");
ContractUtils.RequiresNotNull(options, "options");
PythonCompilerOptions compilerOptions = context.Options as PythonCompilerOptions;
if (options == null) {
throw new ValueErrorException(Resources.PythonContextRequired);
}
SourceCodeReader reader;
try {
reader = context.SourceUnit.GetReader();
if (compilerOptions.SkipFirstLine) {
reader.ReadLine();
}
} catch (IOException e) {
context.Errors.Add(context.SourceUnit, e.Message, SourceSpan.Invalid, 0, Severity.Error);
throw;
}
Tokenizer tokenizer = new Tokenizer(context.Errors, compilerOptions, verbatim);
tokenizer.Initialize(null, reader, context.SourceUnit, SourceLocation.MinValue);
tokenizer.IndentationInconsistencySeverity = options.IndentationInconsistencySeverity;
Parser result = new Parser(context, tokenizer, context.Errors, context.ParserSink, compilerOptions.Module);
result._sourceReader = reader;
return result;
}
#endregion
#region Public parser interface
public PythonAst ParseFile(bool makeModule) {
return ParseFile(makeModule, false);
}
//single_input: Newline | simple_stmt | compound_stmt Newline
//eval_input: testlist Newline* ENDMARKER
//file_input: (Newline | stmt)* ENDMARKER
public PythonAst ParseFile(bool makeModule, bool returnValue) {
try {
return ParseFileWorker(makeModule, returnValue);
} catch (BadSourceException bse) {
throw BadSourceError(bse);
}
}
//[stmt_list] Newline | compound_stmt Newline
//stmt_list ::= simple_stmt (";" simple_stmt)* [";"]
//compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | funcdef | classdef
//Returns a simple or coumpound_stmt or null if input is incomplete
/// <summary>
/// Parse one or more lines of interactive input
/// </summary>
/// <returns>null if input is not yet valid but could be with more lines</returns>
public PythonAst ParseInteractiveCode(out ScriptCodeParseResult properties) {
bool parsingMultiLineCmpdStmt;
bool isEmptyStmt = false;
properties = ScriptCodeParseResult.Complete;
_globalParent = new PythonAst(false, _languageFeatures, true, _context);
StartParsing();
Statement ret = InternalParseInteractiveInput(out parsingMultiLineCmpdStmt, out isEmptyStmt);
if (_errorCode == 0) {
if (isEmptyStmt) {
properties = ScriptCodeParseResult.Empty;
} else if (parsingMultiLineCmpdStmt) {
properties = ScriptCodeParseResult.IncompleteStatement;
}
if (isEmptyStmt) {
return null;
}
return FinishParsing(ret);
} else {
if ((_errorCode & ErrorCodes.IncompleteMask) != 0) {
if ((_errorCode & ErrorCodes.IncompleteToken) != 0) {
properties = ScriptCodeParseResult.IncompleteToken;
return null;
}
if ((_errorCode & ErrorCodes.IncompleteStatement) != 0) {
if (parsingMultiLineCmpdStmt) {
properties = ScriptCodeParseResult.IncompleteStatement;
} else {
properties = ScriptCodeParseResult.IncompleteToken;
}
return null;
}
}
properties = ScriptCodeParseResult.Invalid;
return null;
}
}
private PythonAst FinishParsing(Statement ret) {
var res = _globalParent;
_globalParent = null;
var lineLocs = _tokenizer.GetLineLocations();
// update line mapping
if (_sourceUnit.HasLineMapping) {
List<int> newLineMapping = new List<int>();
int last = 0;
for (int i = 0; i < lineLocs.Length; i++) {
while (newLineMapping.Count < i) {
newLineMapping.Add(last);
}
last = lineLocs[i] + 1;
newLineMapping.Add(lineLocs[i]);
}
lineLocs = newLineMapping.ToArray();
}
res.ParsingFinished(lineLocs, ret, _languageFeatures);
return res;
}
public PythonAst ParseSingleStatement() {
try {
_globalParent = new PythonAst(false, _languageFeatures, true, _context);
StartParsing();
MaybeEatNewLine();
Statement statement = ParseStmt();
EatEndOfInput();
return FinishParsing(statement);
} catch (BadSourceException bse) {
throw BadSourceError(bse);
}
}
public PythonAst ParseTopExpression() {
try {
// TODO: move from source unit .TrimStart(' ', '\t')
_globalParent = new PythonAst(false, _languageFeatures, false, _context);
ReturnStatement ret = new ReturnStatement(ParseTestListAsExpression());
ret.SetLoc(_globalParent, 0, 0);
return FinishParsing(ret);
} catch (BadSourceException bse) {
throw BadSourceError(bse);
}
}
/// <summary>
/// Given the interactive text input for a compound statement, calculate what the
/// indentation level of the next line should be
/// </summary>
public static int GetNextAutoIndentSize(string text, int autoIndentTabWidth) {
ContractUtils.RequiresNotNull(text, "text");
Debug.Assert(text[text.Length - 1] == '\n');
string[] lines = text.Split(newLineChar);
if (lines.Length <= 1) return 0;
string lastLine = lines[lines.Length - 2];
// Figure out the number of white-spaces at the start of the last line
int startingSpaces = 0;
while (startingSpaces < lastLine.Length && lastLine[startingSpaces] == ' ')
startingSpaces++;
// Assume the same indent as the previous line
int autoIndentSize = startingSpaces;
// Increase the indent if this looks like the start of a compounds statement.
// Ideally, we would ask the parser to tell us the exact indentation level
if (lastLine.TrimEnd(whiteSpace).EndsWith(":"))
autoIndentSize += autoIndentTabWidth;
return autoIndentSize;
}
public ErrorSink ErrorSink {
get {
return _errors;
}
set {
ContractUtils.RequiresNotNull(value, "value");
_errors = value;
}
}
public ParserSink ParserSink {
get {
return _sink;
}
set {
if (_sink == ParserSink.Null) {
_sink = null;
} else {
_sink = value;
}
}
}
public int ErrorCode {
get { return _errorCode; }
}
public void Reset(SourceUnit sourceUnit, ModuleOptions languageFeatures) {
ContractUtils.RequiresNotNull(sourceUnit, "sourceUnit");
_sourceUnit = sourceUnit;
_languageFeatures = languageFeatures;
_token = new TokenWithSpan();
_lookahead = new TokenWithSpan();
_fromFutureAllowed = true;
_functions = null;
_privatePrefix = null;
_parsingStarted = false;
_errorCode = 0;
}
public void Reset() {
Reset(_sourceUnit, _languageFeatures);
}
#endregion
#region Error Reporting
private void ReportSyntaxError(TokenWithSpan t) {
ReportSyntaxError(t, ErrorCodes.SyntaxError);
}
private void ReportSyntaxError(TokenWithSpan t, int errorCode) {
ReportSyntaxError(t.Token, t.Span, errorCode, true);
}
private void ReportSyntaxError(Token t, IndexSpan span, int errorCode, bool allowIncomplete) {
var start = span.Start;
var end = span.End;
if (allowIncomplete && (t.Kind == TokenKind.EndOfFile || (_tokenizer.IsEndOfFile && (t.Kind == TokenKind.Dedent || t.Kind == TokenKind.NLToken)))) {
errorCode |= ErrorCodes.IncompleteStatement;
}
string msg = String.Format(System.Globalization.CultureInfo.InvariantCulture, GetErrorMessage(t, errorCode), t.Image);
ReportSyntaxError(start, end, msg, errorCode);
}
private static string GetErrorMessage(Token t, int errorCode) {
string msg;
if ((errorCode & ~ErrorCodes.IncompleteMask) == ErrorCodes.IndentationError) {
msg = Resources.ExpectedIndentation;
} else if (t.Kind != TokenKind.EndOfFile) {
msg = Resources.UnexpectedToken;
} else {
msg = "unexpected EOF while parsing";
}
return msg;
}
private void ReportSyntaxError(string message) {
ReportSyntaxError(_lookahead.Span.Start, _lookahead.Span.End, message);
}
internal void ReportSyntaxError(int start, int end, string message) {
ReportSyntaxError(start, end, message, ErrorCodes.SyntaxError);
}
internal void ReportSyntaxError(int start, int end, string message, int errorCode) {
// save the first one, the next error codes may be induced errors:
if (_errorCode == 0) {
_errorCode = errorCode;
}
_errors.Add(_sourceUnit,
message,
new SourceSpan(_tokenizer.IndexToLocation(start), _tokenizer.IndexToLocation(end)),
errorCode,
Severity.FatalError);
}
#endregion
#region LL(1) Parsing
private static bool IsPrivateName(string name) {
return name.StartsWith("__") && !name.EndsWith("__");
}
private string FixName(string name) {
if (_privatePrefix != null && IsPrivateName(name)) {
name = "_" + _privatePrefix + name;
}
return name;
}
private string ReadNameMaybeNone() {
// peek for better error recovery
Token t = PeekToken();
if (t == Tokens.NoneToken) {
NextToken();
return "None";
}
NameToken n = t as NameToken;
if (n == null) {
ReportSyntaxError("syntax error");
return null;
}
NextToken();
return FixName(n.Name);
}
private string ReadName() {
NameToken n = PeekToken() as NameToken;
if (n == null) {
ReportSyntaxError(_lookahead);
return null;
}
NextToken();
return FixName(n.Name);
}
//stmt: simple_stmt | compound_stmt
//compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | funcdef | classdef
private Statement ParseStmt() {
switch (PeekToken().Kind) {
case TokenKind.KeywordIf:
return ParseIfStmt();
case TokenKind.KeywordWhile:
return ParseWhileStmt();
case TokenKind.KeywordFor:
return ParseForStmt();
case TokenKind.KeywordTry:
return ParseTryStatement();
case TokenKind.At:
return ParseDecorated();
case TokenKind.KeywordDef:
return ParseFuncDef();
case TokenKind.KeywordClass:
return ParseClassDef();
case TokenKind.KeywordWith:
return ParseWithStmt();
default:
return ParseSimpleStmt();
}
}
//simple_stmt: small_stmt (';' small_stmt)* [';'] Newline
private Statement ParseSimpleStmt() {
Statement s = ParseSmallStmt();
if (MaybeEat(TokenKind.Semicolon)) {
var start = s.StartIndex;
List<Statement> l = new List<Statement>();
l.Add(s);
while (true) {
if (MaybeEatNewLine() || MaybeEat(TokenKind.EndOfFile)) {
break;
}
l.Add(ParseSmallStmt());
if (MaybeEat(TokenKind.EndOfFile)) {
// implies a new line
break;
} else if (!MaybeEat(TokenKind.Semicolon)) {
EatNewLine();
break;
}
}
Statement[] stmts = l.ToArray();
SuiteStatement ret = new SuiteStatement(stmts);
ret.SetLoc(_globalParent, start, stmts[stmts.Length - 1].EndIndex);
return ret;
} else if (!MaybeEat(TokenKind.EndOfFile) && !EatNewLine()) {
// error handling, make sure we're making forward progress
NextToken();
}
return s;
}
/*
small_stmt: expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | import_stmt | global_stmt | exec_stmt | assert_stmt
del_stmt: 'del' exprlist
pass_stmt: 'pass'
flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt
break_stmt: 'break'
continue_stmt: 'continue'
return_stmt: 'return' [testlist]
yield_stmt: 'yield' testlist
*/
private Statement ParseSmallStmt() {
switch (PeekToken().Kind) {
case TokenKind.KeywordPass:
return FinishSmallStmt(new EmptyStatement());
case TokenKind.KeywordBreak:
if (!_inLoop) {
ReportSyntaxError("'break' outside loop");
}
return FinishSmallStmt(new BreakStatement());
case TokenKind.KeywordContinue:
if (!_inLoop) {
ReportSyntaxError("'continue' not properly in loop");
} else if (_inFinally && !_inFinallyLoop) {
ReportSyntaxError("'continue' not supported inside 'finally' clause");
}
return FinishSmallStmt(new ContinueStatement());
case TokenKind.KeywordReturn:
return ParseReturnStmt();
case TokenKind.KeywordFrom:
return ParseFromImportStmt();
case TokenKind.KeywordImport:
return ParseImportStmt();
case TokenKind.KeywordGlobal:
return ParseGlobalStmt();
case TokenKind.KeywordRaise:
return ParseRaiseStmt();
case TokenKind.KeywordAssert:
return ParseAssertStmt();
case TokenKind.KeywordExec:
return ParseExecStmt();
case TokenKind.KeywordDel:
return ParseDelStmt();
case TokenKind.KeywordYield:
return ParseYieldStmt();
default:
return ParseExprStmt();
}
}
// del_stmt: "del" target_list
// for error reporting reasons we allow any expression and then report the bad
// delete node when it fails. This is the reason we don't call ParseTargetList.
private Statement ParseDelStmt() {
NextToken();
var start = GetStart();
List<Expression> l = ParseExprList();
foreach (Expression e in l) {
string delError = e.CheckDelete();
if (delError != null) {
ReportSyntaxError(e.StartIndex, e.EndIndex, delError, ErrorCodes.SyntaxError);
}
}
DelStatement ret = new DelStatement(l.ToArray());
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
private Statement ParseReturnStmt() {
if (CurrentFunction == null) {
ReportSyntaxError(IronPython.Resources.MisplacedReturn);
}
NextToken();
Expression expr = null;
var start = GetStart();
if (!NeverTestToken(PeekToken())) {
expr = ParseTestListAsExpr();
}
if (expr != null) {
_returnWithValue = true;
if (_isGenerator) {
ReportSyntaxError("'return' with argument inside generator");
}
}
ReturnStatement ret = new ReturnStatement(expr);
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
private Statement FinishSmallStmt(Statement stmt) {
NextToken();
stmt.SetLoc(_globalParent, GetStart(), GetEnd());
return stmt;
}
private Statement ParseYieldStmt() {
// For yield statements, continue to enforce that it's currently in a function.
// This gives us better syntax error reporting for yield-statements than for yield-expressions.
FunctionDefinition current = CurrentFunction;
if (current == null) {
ReportSyntaxError(IronPython.Resources.MisplacedYield);
}
_isGenerator = true;
if (_returnWithValue) {
ReportSyntaxError("'return' with argument inside generator");
}
Eat(TokenKind.KeywordYield);
// See Pep 342: a yield statement is now just an expression statement around a yield expression.
Expression e = ParseYieldExpression();
Debug.Assert(e != null); // caller already verified we have a yield.
Statement s = new ExpressionStatement(e);
s.SetLoc(_globalParent, e.IndexSpan);
return s;
}
/// <summary>
/// Peek if the next token is a 'yield' and parse a yield expression. Else return null.
///
/// Called w/ yield already eaten.
/// </summary>
/// <returns>A yield expression if present, else null. </returns>
// yield_expression: "yield" [expression_list]
private Expression ParseYieldExpression() {
// Mark that this function is actually a generator.
// If we're in a generator expression, then we don't have a function yet.
// g=((yield i) for i in range(5))
// In that acse, the genexp will mark IsGenerator.
FunctionDefinition current = CurrentFunction;
if (current != null) {
current.IsGenerator = true;
}
var start = GetStart();
// Parse expression list after yield. This can be:
// 1) empty, in which case it becomes 'yield None'
// 2) a single expression
// 3) multiple expression, in which case it's wrapped in a tuple.
Expression yieldResult;
bool trailingComma;
List<Expression> l = ParseExpressionList(out trailingComma);
if (l.Count == 0) {
// Check empty expression and convert to 'none'
yieldResult = new ConstantExpression(null);
// location set to match yield location (consistent with cpython)
yieldResult.SetLoc(_globalParent, start, GetEnd());
} else if (l.Count != 1) {
// make a tuple
yieldResult = MakeTupleOrExpr(l, trailingComma);
} else {
// just take the single expression
yieldResult = l[0];
}
Expression yieldExpression = new YieldExpression(yieldResult);
yieldExpression.SetLoc(_globalParent, start, GetEnd());
return yieldExpression;
}
private Statement FinishAssignments(Expression right) {
List<Expression> left = null;
Expression singleLeft = null;
while (MaybeEat(TokenKind.Assign)) {
string assignError = right.CheckAssign();
if (assignError != null) {
ReportSyntaxError(right.StartIndex, right.EndIndex, assignError, ErrorCodes.SyntaxError | ErrorCodes.NoCaret);
}
if (singleLeft == null) {
singleLeft = right;
} else {
if (left == null) {
left = new List<Expression>();
left.Add(singleLeft);
}
left.Add(right);
}
if (MaybeEat(TokenKind.KeywordYield)) {
right = ParseYieldExpression();
} else {
right = ParseTestListAsExpr();
}
}
if (left != null) {
Debug.Assert(left.Count > 0);
AssignmentStatement assign = new AssignmentStatement(left.ToArray(), right);
assign.SetLoc(_globalParent, left[0].StartIndex, right.EndIndex);
return assign;
} else {
Debug.Assert(singleLeft != null);
AssignmentStatement assign = new AssignmentStatement(new[] { singleLeft }, right);
assign.SetLoc(_globalParent, singleLeft.StartIndex, right.EndIndex);
return assign;
}
}
// expr_stmt: expression_list
// expression_list: expression ( "," expression )* [","]
// assignment_stmt: (target_list "=")+ (expression_list | yield_expression)
// augmented_assignment_stmt ::= target augop (expression_list | yield_expression)
// augop: '+=' | '-=' | '*=' | '/=' | '%=' | '**=' | '>>=' | '<<=' | '&=' | '^=' | '|=' | '//='
private Statement ParseExprStmt() {
Expression ret = ParseTestListAsExpr();
if (ret is ErrorExpression) {
NextToken();
}
if (PeekToken(TokenKind.Assign)) {
return FinishAssignments(ret);
} else {
PythonOperator op = GetAssignOperator(PeekToken());
if (op != PythonOperator.None) {
NextToken();
Expression rhs;
if (MaybeEat(TokenKind.KeywordYield)) {
rhs = ParseYieldExpression();
} else {
rhs = ParseTestListAsExpr();
}
string assignError = ret.CheckAugmentedAssign();
if (assignError != null) {
ReportSyntaxError(assignError);
}
AugmentedAssignStatement aug = new AugmentedAssignStatement(op, ret, rhs);
aug.SetLoc(_globalParent, ret.StartIndex, GetEnd());
return aug;
} else {
Statement stmt = new ExpressionStatement(ret);
stmt.SetLoc(_globalParent, ret.IndexSpan);
return stmt;
}
}
}
private PythonOperator GetAssignOperator(Token t) {
switch (t.Kind) {
case TokenKind.AddEqual: return PythonOperator.Add;
case TokenKind.SubtractEqual: return PythonOperator.Subtract;
case TokenKind.MultiplyEqual: return PythonOperator.Multiply;
case TokenKind.DivideEqual: return TrueDivision ? PythonOperator.TrueDivide : PythonOperator.Divide;
case TokenKind.ModEqual: return PythonOperator.Mod;
case TokenKind.BitwiseAndEqual: return PythonOperator.BitwiseAnd;
case TokenKind.BitwiseOrEqual: return PythonOperator.BitwiseOr;
case TokenKind.ExclusiveOrEqual: return PythonOperator.Xor;
case TokenKind.LeftShiftEqual: return PythonOperator.LeftShift;
case TokenKind.RightShiftEqual: return PythonOperator.RightShift;
case TokenKind.PowerEqual: return PythonOperator.Power;
case TokenKind.FloorDivideEqual: return PythonOperator.FloorDivide;
default: return PythonOperator.None;
}
}
private PythonOperator GetBinaryOperator(OperatorToken token) {
switch (token.Kind) {
case TokenKind.Add: return PythonOperator.Add;
case TokenKind.Subtract: return PythonOperator.Subtract;
case TokenKind.Multiply: return PythonOperator.Multiply;
case TokenKind.Divide: return TrueDivision ? PythonOperator.TrueDivide : PythonOperator.Divide;
case TokenKind.Mod: return PythonOperator.Mod;
case TokenKind.BitwiseAnd: return PythonOperator.BitwiseAnd;
case TokenKind.BitwiseOr: return PythonOperator.BitwiseOr;
case TokenKind.ExclusiveOr: return PythonOperator.Xor;
case TokenKind.LeftShift: return PythonOperator.LeftShift;
case TokenKind.RightShift: return PythonOperator.RightShift;
case TokenKind.Power: return PythonOperator.Power;
case TokenKind.FloorDivide: return PythonOperator.FloorDivide;
default:
string message = String.Format(
System.Globalization.CultureInfo.InvariantCulture,
Resources.UnexpectedToken,
token.Kind);
Debug.Assert(false, message);
throw new ValueErrorException(message);
}
}
// import_stmt: 'import' module ['as' name"] (',' module ['as' name])*
// name: identifier
private ImportStatement ParseImportStmt() {
Eat(TokenKind.KeywordImport);
var start = GetStart();
List<ModuleName> l = new List<ModuleName>();
List<string> las = new List<string>();
l.Add(ParseModuleName());
las.Add(MaybeParseAsName());
while (MaybeEat(TokenKind.Comma)) {
l.Add(ParseModuleName());
las.Add(MaybeParseAsName());
}
ModuleName[] names = l.ToArray();
var asNames = las.ToArray();
ImportStatement ret = new ImportStatement(names, asNames, AbsoluteImports);
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
// module: (identifier '.')* identifier
private ModuleName ParseModuleName() {
var start = GetStart();
ModuleName ret = new ModuleName(ReadNames());
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
// relative_module: "."* module | "."+
private ModuleName ParseRelativeModuleName() {
var start = GetStart();
int dotCount = 0;
while (MaybeEat(TokenKind.Dot)) {
dotCount++;
}
string[] names = ArrayUtils.EmptyStrings;
if (PeekToken() is NameToken) {
names = ReadNames();
}
ModuleName ret;
if (dotCount > 0) {
ret = new RelativeModuleName(names, dotCount);
} else {
if (names.Length == 0) {
ReportSyntaxError(_lookahead.Span.Start, _lookahead.Span.End, "invalid syntax");
}
ret = new ModuleName(names);
}
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
private string[] ReadNames() {
List<string> l = new List<string>();
l.Add(ReadName());
while (MaybeEat(TokenKind.Dot)) {
l.Add(ReadName());
}
return l.ToArray();
}
// 'from' relative_module 'import' identifier ['as' name] (',' identifier ['as' name]) *
// 'from' relative_module 'import' '(' identifier ['as' name] (',' identifier ['as' name])* [','] ')'
// 'from' module 'import' "*"
private FromImportStatement ParseFromImportStmt() {
Eat(TokenKind.KeywordFrom);
var start = GetStart();
ModuleName dname = ParseRelativeModuleName();
Eat(TokenKind.KeywordImport);
bool ateParen = MaybeEat(TokenKind.LeftParenthesis);
string[] names;
string[] asNames;
bool fromFuture = false;
if (MaybeEat(TokenKind.Multiply)) {
names = (string[])FromImportStatement.Star;
asNames = null;
} else {
List<string> l = new List<string>();
List<string> las = new List<string>();
if (MaybeEat(TokenKind.LeftParenthesis)) {
ParseAsNameList(l, las);
Eat(TokenKind.RightParenthesis);
} else {
ParseAsNameList(l, las);
}
names = l.ToArray();
asNames = las.ToArray();
}
// Process from __future__ statement
if (dname.Names.Count == 1 && dname.Names[0] == "__future__") {
if (!_fromFutureAllowed) {
ReportSyntaxError(IronPython.Resources.MisplacedFuture);
}
if (names == FromImportStatement.Star) {
ReportSyntaxError(IronPython.Resources.NoFutureStar);
}
fromFuture = true;
foreach (string name in names) {
if (name == "division") {
_languageFeatures |= ModuleOptions.TrueDivision;
} else if (name == "with_statement") {
_languageFeatures |= ModuleOptions.WithStatement;
} else if (name == "absolute_import") {
_languageFeatures |= ModuleOptions.AbsoluteImports;
} else if (name == "print_function") {
// Ignored in Python 3
} else if (name == "unicode_literals") {
_tokenizer.UnicodeLiterals = true;
_languageFeatures |= ModuleOptions.UnicodeLiterals;
} else if (name == "nested_scopes") {
} else if (name == "generators") {
} else {
string strName = name;
fromFuture = false;
if (strName != "braces") {
ReportSyntaxError(IronPython.Resources.UnknownFutureFeature + strName);
} else {
// match CPython error message
ReportSyntaxError(IronPython.Resources.NotAChance);
}
}
}
}
if (ateParen) {
Eat(TokenKind.RightParenthesis);
}
FromImportStatement ret = new FromImportStatement(dname, (string[])names, asNames, fromFuture, AbsoluteImports);
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
// import_as_name (',' import_as_name)*
private void ParseAsNameList(List<string> l, List<string> las) {
l.Add(ReadName());
las.Add(MaybeParseAsName());
while (MaybeEat(TokenKind.Comma)) {
if (PeekToken(TokenKind.RightParenthesis)) return; // the list is allowed to end with a ,
l.Add(ReadName());
las.Add(MaybeParseAsName());
}
}
//import_as_name: NAME [NAME NAME]
//dotted_as_name: dotted_name [NAME NAME]
private string MaybeParseAsName() {
if (MaybeEat(TokenKind.KeywordAs)) {
return ReadName();
}
return null;
}
//exec_stmt: 'exec' expr ['in' expression [',' expression]]
private ExecStatement ParseExecStmt() {
Eat(TokenKind.KeywordExec);
var start = GetStart();
Expression code, locals = null, globals = null;
code = ParseExpr();
if (MaybeEat(TokenKind.KeywordIn)) {
globals = ParseExpression();
if (MaybeEat(TokenKind.Comma)) {
locals = ParseExpression();
}
}
ExecStatement ret = new ExecStatement(code, locals, globals);
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
//global_stmt: 'global' NAME (',' NAME)*
private GlobalStatement ParseGlobalStmt() {
Eat(TokenKind.KeywordGlobal);
var start = GetStart();
List<string> l = new List<string>();
l.Add(ReadName());
while (MaybeEat(TokenKind.Comma)) {
l.Add(ReadName());
}
string[] names = l.ToArray();
GlobalStatement ret = new GlobalStatement(names);
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}
//raise_stmt: 'raise' [expression [',' expression [',' expression]]]
private RaiseStatement ParseRaiseStmt() {
Eat(TokenKind.KeywordRaise);
var start = GetStart();
Expression type = null, _value = null, traceback = null;
if (!NeverTestToken(PeekToken())) {
type = ParseExpression();
if (MaybeEat(TokenKind.Comma)) {
_value = ParseExpression();
if (MaybeEat(TokenKind.Comma)) {
traceback = ParseExpression();
}
}
}
RaiseStatement ret = new RaiseStatement(type, _value, traceback);
ret.SetLoc(_globalParent, start, GetEnd());
return ret;
}