Statement ParseStatement(Scope scope)
{
int startP = reader.p;
int startLine = reader.Peek().Line;
Statement stat = null;
// print(tok.Peek().Print())
if (reader.ConsumeKeyword("if"))
{
//setup
IfStmt _if = new IfStmt();
//clauses
do
{
int sP = reader.p;
Expression nodeCond = ParseExpr(scope);
if (!reader.ConsumeKeyword("then"))
error("'then' expected");
List<Statement> nodeBody = ParseStatementList(scope);
List<Token> range = new List<Token>();
range.Add(reader.tokens[sP - 1]);
range.AddRange(reader.Range(sP, reader.p));
_if.Clauses.Add(new ElseIfStmt(scope)
{
Condition = nodeCond,
Body = nodeBody,
ScannedTokens = range
});
}
while (reader.ConsumeKeyword("elseif"));
// else clause
if (reader.ConsumeKeyword("else"))
{
int sP = reader.p;
List<Statement> nodeBody = ParseStatementList(scope);
List<Token> range = new List<Token>();
range.Add(reader.tokens[sP - 1]);
range.AddRange(reader.Range(sP, reader.p));
_if.Clauses.Add(new ElseStmt(scope)
{
Body = nodeBody,
ScannedTokens = range
});
}
// end
if (!reader.ConsumeKeyword("end"))
error("'end' expected");
stat = _if;
}
else if (reader.ConsumeKeyword("while"))
{
WhileStatement w = new WhileStatement(scope);
// condition
Expression nodeCond = ParseExpr(scope);
// do
if (!reader.ConsumeKeyword("do"))
error("'do' expected");
// body
List<Statement> body = ParseStatementList(scope);
//end
if (!reader.ConsumeKeyword("end"))
error("'end' expected");
// return
w.Condition = nodeCond;
w.Body = body;
stat = w;
}
else if (reader.ConsumeKeyword("do"))
{
// do block
List<Statement> b = ParseStatementList(scope);
if (!reader.ConsumeKeyword("end"))
error("'end' expected");
stat = new DoStatement(scope) { Body = b };
}
else if (reader.ConsumeKeyword("for"))
{
//for block
if (!reader.Is(TokenType.Ident))
error("<ident> expected");
Token baseVarName = reader.Get();
if (reader.ConsumeSymbol('='))
{
//numeric for
NumericForStatement forL = new NumericForStatement(scope);
Variable forVar = new Variable() { Name = baseVarName.Data };
forL.Scope.AddLocal(forVar);
Expression startEx = ParseExpr(scope);
if (!reader.ConsumeSymbol(','))
error("',' expected");
Expression endEx = ParseExpr(scope);
Expression stepEx = null;
if (reader.ConsumeSymbol(','))
{
stepEx = ParseExpr(scope);
}
if (!reader.ConsumeKeyword("do"))
error("'do' expected");
List<Statement> body = ParseStatementList(forL.Scope);
if (!reader.ConsumeKeyword("end"))
error("'end' expected");
forL.Variable = forVar;
forL.Start = startEx;
forL.End = endEx;
forL.Step = stepEx;
forL.Body = body;
stat = forL;
}
else
{
// generic for
GenericForStatement forL = new GenericForStatement(scope);
List<Variable> varList = new List<Variable> { forL.Scope.CreateLocal(baseVarName.Data) };
while (reader.ConsumeSymbol(','))
{
if (!reader.Is(TokenType.Ident))
error("for variable expected");
varList.Add(forL.Scope.CreateLocal(reader.Get().Data));
}
if (!reader.ConsumeKeyword("in"))
error("'in' expected");
List<Expression> generators = new List<Expression>();
Expression first = ParseExpr(scope);
generators.Add(first);
while (reader.ConsumeSymbol(','))
{
Expression gen = ParseExpr(scope);
generators.Add(gen);
}
if (!reader.ConsumeKeyword("do"))
error("'do' expected");
List<Statement> body = ParseStatementList(forL.Scope);
if (!reader.ConsumeKeyword("end"))
error("'end' expected");
forL.VariableList = varList;
forL.Generators = generators;
forL.Body = body;
stat = forL;
}
}
else if (reader.ConsumeKeyword("repeat"))
{
List<Statement> body = ParseStatementList(scope);
if (!reader.ConsumeKeyword("until"))
error("'until' expected");
Expression cond = ParseExpr(scope);
RepeatStatement r = new RepeatStatement(scope);
r.Condition = cond;
r.Body = body;
stat = r;
}
else if (reader.ConsumeKeyword("function"))
{
if (!reader.Is(TokenType.Ident))
error("function name expected");
Expression name = ParseSuffixedExpr(scope, true);
// true: only dots and colons
FunctionStatement func = ParseFunctionArgsAndBody(scope);
func.IsLocal = false;
func.Name = name;
stat = func;
}
else if (reader.ConsumeKeyword("local"))
{
if (reader.Is(TokenType.Ident))
{
List<string> varList = new List<string> { reader.Get().Data };
while (reader.ConsumeSymbol(','))
{
if (!reader.Is(TokenType.Ident))
error("local variable name expected");
varList.Add(reader.Get().Data);
}
List<Expression> initList = new List<Expression>();
if (reader.ConsumeSymbol('='))
{
do
{
Expression ex = ParseExpr(scope);
initList.Add(ex);
} while (reader.ConsumeSymbol(','));
}
//now patch var list
//we can't do this before getting the init list, because the init list does not
//have the locals themselves in scope.
List<Expression> newVarList = new List<Expression>();
for (int i = 0; i < varList.Count; i++)
{
Variable x = scope.CreateLocal(varList[i]);
newVarList.Add(new VariableExpression { Var = x });
}
AssignmentStatement l = new AssignmentStatement();
l.Lhs = newVarList;
l.Rhs = initList;
l.IsLocal = true;
stat = l;
}
else if (reader.ConsumeKeyword("function"))
{
if (!reader.Is(TokenType.Ident))
error("Function name expected");
string name = reader.Get().Data;
Variable localVar = scope.CreateLocal(name);
FunctionStatement func = ParseFunctionArgsAndBody(scope);
func.Name = new VariableExpression { Var = localVar };
func.IsLocal = true;
stat = func;
}
else
error("local variable or function definition expected");
}
#if !VANILLA_LUA
else if (reader.ConsumeSymbol("::"))
{
if (!reader.Is(TokenType.Ident))
error("label name expected");
string label = reader.Get().Data;
if (!reader.ConsumeSymbol("::"))
error("'::' expected");
LabelStatement l = new LabelStatement();
l.Label = label;
stat = l;
}
#endif
else if (reader.ConsumeKeyword("return"))
{
List<Expression> exprList = new List<Expression>();
if (!reader.IsKeyword("end") && !reader.IsEof())
{
Expression firstEx = ParseExpr(scope);
exprList.Add(firstEx);
while (reader.ConsumeSymbol(','))
{
Expression ex = ParseExpr(scope);
exprList.Add(ex);
}
}
ReturnStatement r = new ReturnStatement();
r.Arguments = exprList;
stat = r;
}
else if (reader.ConsumeKeyword("break"))
{
stat = new BreakStatement();
}
else if (reader.ConsumeKeyword("continue"))
{
stat = new ContinueStatement();
}
#if !VANILLA_LUA
else if (reader.ConsumeKeyword("goto"))
{
if (!reader.Is(TokenType.Ident))
error("label expected");
string label = reader.Get().Data;
GotoStatement g = new GotoStatement();
g.Label = label;
stat = g;
}
else if (reader.ConsumeKeyword("using"))
{
// using <a, b = 1, x()> do <statements> end
UsingStatement us = new UsingStatement(scope);
us.Scope = new Scope(scope);
List<Expression> lhs = new List<Expression> { ParseExpr(us.Scope) };
while (reader.ConsumeSymbol(','))
{
lhs.Add(ParseSuffixedExpr(us.Scope, true));
}
// equals
if (!reader.ConsumeSymbol('='))
error("'=' expected");
//rhs
List<Expression> rhs = new List<Expression>();
rhs.Add(ParseExpr(us.Scope));
while (reader.ConsumeSymbol(','))
{
rhs.Add(ParseExpr(scope));
}
AssignmentStatement a = new AssignmentStatement();
a.Lhs = lhs;
a.Rhs = rhs;
a.IsLocal = true;
if (!reader.ConsumeKeyword("do"))
error("'do' expected");
List<Statement> block = ParseStatementList(us.Scope);
if (!reader.ConsumeKeyword("end"))
error("'end' expected");
us.Vars = a;
us.Body = block;
stat = us;
}
#endif
else
{
// statementParseExpr
Expression suffixed = ParseSuffixedExpr(scope);
// assignment or call?
if (reader.IsSymbol(',') || reader.IsSymbol('='))
{
// check that it was not parenthesized, making it not an lvalue
if (suffixed.ParenCount > 0)
error("Can not assign to parenthesized expression, it is not an lvalue");
// more processing needed
List<Expression> lhs = new List<Expression> { suffixed };
while (reader.ConsumeSymbol(','))
{
lhs.Add(ParseSuffixedExpr(scope));
}
// equals
if (!reader.ConsumeSymbol('='))
error("'=' expected");
//rhs
List<Expression> rhs = new List<Expression>();
rhs.Add(ParseExpr(scope));
while (reader.ConsumeSymbol(','))
{
rhs.Add(ParseExpr(scope));
}
AssignmentStatement a = new AssignmentStatement();
a.Lhs = lhs;
a.Rhs = rhs;
stat = a;
}
#if !VANILLA_LUA
else if (isAugmentedAssignment(reader.Peek()))
{
AugmentedAssignmentStatement aas = new AugmentedAssignmentStatement();
Expression left = suffixed;
Expression right = null;
string augmentedOp = reader.Get().Data;
right = ParseExpr(scope);
BinOpExpr nRight = new BinOpExpr();
nRight.Lhs = left;
nRight.Op = augmentedOp.Substring(0, augmentedOp.Length - 1); // strip the '='
nRight.Rhs = right;
aas.Lhs = new List<Expression> { left };
aas.Rhs = new List<Expression> { nRight };
stat = aas;
}
#endif
else if (suffixed is CallExpr ||
suffixed is TableCallExpr ||
suffixed is StringCallExpr)
{
//it's a call statement
CallStatement c = new CallStatement();
c.Expression = suffixed;
stat = c;
}
else
error("assignment statement expected");
}
stat.ScannedTokens = reader.Range(startP, reader.p);
if (reader.Peek().Data == ";" && reader.Peek().Type == TokenType.Symbol)
{
stat.HasSemicolon = true;
stat.SemicolonToken = reader.Get();
}
if (stat.Scope == null)
stat.Scope = scope;
stat.LineNumber = startLine;
return stat;
}
Expression ParseSubExpr(Scope scope, int level)
{
// base item, possibly with unop prefix
Expression exp = null;
if (isUnOp(reader.Peek().Data) &&
(reader.Peek().Type == TokenType.Symbol || reader.Peek().Type == TokenType.Keyword))
{
string op = reader.Get().Data;
exp = ParseSubExpr(scope, unopprio);
exp = new UnOpExpr { Rhs = exp, Op = op };
}
else
exp = ParseSimpleExpr(scope);
if (exp is InlineFunctionExpression)
return exp; // inline functions cannot have any extra parts
// next items in chain
while (true)
{
priority_ prio = getpriority(reader.Peek().Data);
if (prio != null && prio.l > level)
{
string op = reader.Get().Data;
Expression rhs = ParseSubExpr(scope, prio.r);
BinOpExpr binOpExpr = new BinOpExpr();
binOpExpr.Lhs = exp;
binOpExpr.Op = op;
binOpExpr.Rhs = rhs;
exp = binOpExpr;
}
else
break;
}
return exp;
}