} // ParseFunction
// Parse a Block. The stream should be positioned at the "{" token.
private StmtFrag ParseBlock(FunctionInfo info)
{
StmtFrag frag = gen.NewStmtFrag(tok.Prev().loc);
tok.MatchOp("{");
while (!tok.TryMatchOp("}"))
frag.Append(ParseStatement(info));
return frag;
} // ParseBlock
} // ParseProgram
// Parse a SourceElements (i.e. the main program, or a function body)
// and return the generated code.
private StmtFrag ParseSourceElements( FunctionInfo info,
CGFuncInfo cgFuncInfo )
{
SrcLoc loc;
loc.lineNum = 1;
loc.colNum = 1;
loc.absPosition = 0;
loc.len = 1;
StmtFrag frag = gen.NewStmtFrag(loc);
while (!tok.atEnd && !tok.PeekOp("}"))
if (tok.TryMatchKeyword("function"))
ParseFunction(info.GetNextChild(), false);
else
frag.Append(ParseStatement(info));
return frag;
} // ParseSourceElements
} // ParseForStatement
// Parse a Statement.
private StmtFrag ParseStatement(FunctionInfo info)
{
StringCollection labels = MatchLabelSet();
if (tok.TryMatchKeyword("do"))
{
LoopInfo loopInfo = gen.NewLoopInfo( curCGFuncInfo, tok.Prev().loc,
labels );
loops.Push(loopInfo);
StmtFrag body = ParseStatement(info);
tok.MatchKeyword("while");
tok.MatchOp("(");
ExprFrag condition = ParseExpression(info, true);
tok.MatchOp(")");
tok.MatchOp(";");
LoopInfo temp = (LoopInfo) loops.Pop();
Trace.Assert(temp == loopInfo);
return gen.DoWhile(loopInfo, body, condition);
}
else if (tok.TryMatchKeyword("while"))
{
LoopInfo loopInfo = gen.NewLoopInfo( curCGFuncInfo, tok.Prev().loc,
labels );
loops.Push(loopInfo);
tok.MatchOp("(");
ExprFrag condition = ParseExpression(info, true);
tok.MatchOp(")");
StmtFrag body = ParseStatement(info);
LoopInfo temp = (LoopInfo) loops.Pop();
Trace.Assert(temp == loopInfo);
return gen.WhileDo(loopInfo, condition, body);
}
else if (tok.TryMatchKeyword("for"))
return ParseForStatement(info, labels);
else
{
bool isSwitch = tok.PeekKeyword("switch");
LoopInfo labelInfo = null;
if (labels != null || isSwitch)
{
labelInfo = gen.NewLabeledStmtInfo( curCGFuncInfo, tok.Prev().loc,
labels, isSwitch );
loops.Push(labelInfo);
}
StmtFrag stmt;
if (tok.PeekOp("{"))
stmt = ParseBlock(info);
else if (tok.TryMatchKeyword("var"))
{
stmt = gen.NewStmtFrag(tok.Prev().loc);
do
{
string varName;
SrcLoc varLoc;
stmt.Append(ParseVariableDeclaration( info, true, out varName,
out varLoc ));
}
while (tok.TryMatchOp(","));
tok.MatchOp(";");
}
else if (tok.TryMatchOp(";"))
{
// EmptyStatement
stmt = gen.NewStmtFrag(tok.Prev().loc);
}
else if (tok.TryMatchKeyword("if"))
{
SrcLoc ifLoc = tok.Prev().loc;
tok.MatchOp("(");
ExprFrag condition = ParseExpression(info, true);
tok.MatchOp(")");
StmtFrag ifClause = ParseStatement(info);
StmtFrag elseClause = null;
if (tok.TryMatchKeyword("else"))
elseClause = ParseStatement(info);
stmt = gen.IfThenElse(ifLoc, condition, ifClause, elseClause);
}
else if (tok.TryMatchKeyword("continue"))
{
SrcLoc continueLoc = tok.Prev().loc;
// HACK snewman 8/7/01: the grammar (ContinueStatement) specifies
// "no LineTerminator here".
string id;
tok.TryMatchID(out id);
tok.MatchOp(";");
stmt = gen.Continue(continueLoc, id, CloneStack(loops));
}
else if (tok.TryMatchKeyword("break"))
{
SrcLoc breakLoc = tok.Prev().loc;
// HACK snewman 8/7/01: the grammar (BreakStatement) specifies
// "no LineTerminator here".
string id;
tok.TryMatchID(out id);
tok.MatchOp(";");
stmt = gen.Break(breakLoc, id, CloneStack(loops));
}
else if (tok.TryMatchKeyword("return"))
{
SrcLoc returnLoc = tok.Prev().loc;
// HACK snewman 8/7/01: the grammar (ReturnStatement) specifies
// "no LineTerminator here".
if (tok.TryMatchOp(";"))
stmt = gen.Return(returnLoc, null);
else
{
ExprFrag value = ParseExpression(info, true);
tok.MatchOp(";");
stmt = gen.Return(returnLoc, value);
}
}
else if (tok.TryMatchKeyword("with"))
{
SrcLoc withLoc = tok.Prev().loc;
tok.MatchOp("(");
ExprFrag value = ParseExpression(info, true);
tok.MatchOp(")");
WithInfo withInfo = gen.NewWithInfo(curCGFuncInfo, withLoc);
withs.Push(withInfo);
StmtFrag body = ParseStatement(info);
WithInfo temp = (WithInfo) withs.Pop();
Trace.Assert(temp == withInfo);
stmt = gen.With(withInfo, value, body);
}
else if (tok.TryMatchKeyword("switch"))
{
SrcLoc switchLoc = tok.Prev().loc;
SwitchInfo switchInfo = gen.NewSwitchInfo();
tok.MatchOp("(");
ExprFrag switchValue = ParseExpression(info, true);
tok.MatchOp(")");
tok.MatchOp("{");
while (!tok.TryMatchOp("}"))
{
ExprFrag caseValue;
if (tok.TryMatchKeyword("default"))
caseValue = null;
else
{
tok.MatchKeyword("case");
caseValue = ParseExpression(info, true);
}
StmtFrag clauseStmt = null;
tok.MatchOp(":");
while ( !tok.PeekOp("}") && !tok.PeekKeyword("case") &&
!tok.PeekKeyword("default") )
{
StmtFrag tempStmt = ParseStatement(info);
if (clauseStmt == null)
clauseStmt = tempStmt;
else
clauseStmt.Append(tempStmt);
}
switchInfo.AddCase(caseValue, clauseStmt);
}
stmt = gen.Switch(switchLoc, switchValue, switchInfo);
}
else if (tok.TryMatchKeyword("throw"))
{
SrcLoc throwLoc = tok.Prev().loc;
// HACK snewman 8/7/01: the grammar (ThrowStatement) specifies
// "no LineTerminator here".
ExprFrag value = ParseExpression(info, true);
tok.MatchOp(";");
stmt = gen.Throw(throwLoc, value);
}
else if (tok.TryMatchKeyword("try"))
{
SrcLoc tryLoc = tok.Prev().loc;
StmtFrag tryBody = ParseBlock(info);
String catchVar = null;
WithInfo catchWithInfo = null;
StmtFrag catchBody = null;
StmtFrag finallyBody = null;
if (tok.TryMatchKeyword("catch"))
{
SrcLoc catchLoc = tok.Prev().loc;
tok.MatchOp("(");
catchVar = tok.MatchID();
tok.MatchOp(")");
catchWithInfo = gen.NewWithInfo(curCGFuncInfo, catchLoc);
withs.Push(catchWithInfo);
catchBody = ParseBlock(info);
WithInfo temp = (WithInfo) withs.Pop();
Trace.Assert(temp == catchWithInfo);
}
if (tok.TryMatchKeyword("finally"))
finallyBody = ParseBlock(info);
stmt = gen.TryCatchFinally( tryLoc, tryBody, catchVar,
catchWithInfo, catchBody, finallyBody );
}
else
{
ExprFrag expr = ParseExpression(info, true);
tok.MatchOp(";");
stmt = gen.ExpressionStmt(expr);
}
if (labelInfo != null)
{
LoopInfo temp2 = (LoopInfo) loops.Pop();
Trace.Assert(temp2 == labelInfo);
stmt = gen.LabeledStmt(labelInfo, stmt);
}
return stmt;
}
} // ParseStatement
} // MatchLabelSet
// Parse a for statement. The caller should already have matched
// the "for" keyword.
private StmtFrag ParseForStatement(FunctionInfo info, StringCollection labels)
{
LoopInfo loopInfo = gen.NewLoopInfo(curCGFuncInfo, tok.Prev().loc, labels);
loops.Push(loopInfo);
// HACK snewman 8/13/01: need to review this section against the
// specific semantics for "for" statements, and especially for/in
// statements, in section 12.6 of the ECMA spec.
tok.MatchOp("(");
bool isIn; // True for for/in, false otherwise
StmtFrag init=null; // Initializer; used for both types of loop
ExprFrag cond=null; // Condition; only used for non-in loops
ExprFrag update=null; // Update step; only used for non-in loops
ExprFrag inLHS=null; // LHS expression where in loops put prop names
ExprFrag inRHS=null; // RHS object that in loops iterate over
if (tok.TryMatchKeyword("var"))
{
string varName;
SrcLoc varLoc;
init = ParseVariableDeclaration(info, false, out varName, out varLoc);
isIn = tok.TryMatchKeyword("in");
if (isIn)
inLHS = gen.IdentifierExpr( varLoc, varName, info,
CloneStack(withs) );
else
{
while (tok.TryMatchOp(","))
init.Append(ParseVariableDeclaration( info, false, out varName,
out varLoc ));
}
}
else
{
if (!tok.PeekOp(";"))
{
ExprFrag initExpr = ParseExpression(info, false, 99);
isIn = tok.TryMatchKeyword("in");
if (isIn)
inLHS = initExpr;
else
init = gen.ExpressionStmt(initExpr);
}
else
isIn = false;
}
if (isIn)
inRHS = ParseExpression(info, true);
else
{
tok.MatchOp(";");
if (!tok.PeekOp(";"))
cond = ParseExpression(info, true);
tok.MatchOp(";");
if (!tok.PeekOp(")"))
update = ParseExpression(info, true);
}
tok.MatchOp(")");
StmtFrag body = ParseStatement(info);
LoopInfo temp = (LoopInfo) loops.Pop();
Trace.Assert(temp == loopInfo);
if (isIn)
return gen.ForIn(loopInfo, init, inLHS, inRHS, body);
else
return gen.For(loopInfo, init, cond, update, body);
} // ParseForStatement
