ExpressionParser: Rename some functions and return a syntax error on trailing tokens.

This commit is contained in:
Jordan Woyak 2019-01-08 18:36:58 -06:00
parent 258832b1e8
commit 2b0297489f

View File

@ -818,7 +818,15 @@ class Parser
{
public:
explicit Parser(std::vector<Token> tokens_) : tokens(tokens_) { m_it = tokens.begin(); }
ParseResult Parse() { return Toplevel(); }
ParseResult Parse()
{
ParseResult result = ParseToplevel();
if (Peek().type == TOK_EOF)
return result;
return {ParseStatus::SyntaxError};
}
private:
struct FunctionArguments
@ -859,7 +867,7 @@ private:
{
// Read one argument.
// Grab an expression, but stop at comma.
auto arg = Binary(BinaryOperatorPrecedence(TOK_COMMA));
auto arg = ParseBinary(BinaryOperatorPrecedence(TOK_COMMA));
if (ParseStatus::Successful != arg.status)
return {ParseStatus::SyntaxError};
@ -876,7 +884,7 @@ private:
}
}
ParseResult Atom(const Token& tok)
ParseResult ParseAtom(const Token& tok)
{
switch (tok.type)
{
@ -909,13 +917,13 @@ private:
}
case TOK_LPAREN:
{
return Paren();
return ParseParens();
}
case TOK_SUB:
{
// An atom was expected but we got a subtraction symbol.
// Interpret it as a unary minus function.
return Atom(Token(TOK_FUNCTION, "minus"));
return ParseAtom(Token(TOK_FUNCTION, "minus"));
}
default:
return {ParseStatus::SyntaxError};
@ -955,9 +963,9 @@ private:
}
}
ParseResult Binary(int precedence = 999)
ParseResult ParseBinary(int precedence = 999)
{
ParseResult lhs = Atom(Chew());
ParseResult lhs = ParseAtom(Chew());
if (lhs.status == ParseStatus::SyntaxError)
return lhs;
@ -968,7 +976,7 @@ private:
while (IsBinaryToken(Peek().type) && BinaryOperatorPrecedence(Peek().type) < precedence)
{
const Token tok = Chew();
ParseResult rhs = Binary(BinaryOperatorPrecedence(tok.type));
ParseResult rhs = ParseBinary(BinaryOperatorPrecedence(tok.type));
if (rhs.status == ParseStatus::SyntaxError)
{
return rhs;
@ -980,10 +988,10 @@ private:
return {ParseStatus::Successful, std::move(expr)};
}
ParseResult Paren()
ParseResult ParseParens()
{
// lparen already chewed
ParseResult result = Toplevel();
ParseResult result = ParseToplevel();
if (result.status != ParseStatus::Successful)
return result;
@ -995,7 +1003,7 @@ private:
return result;
}
ParseResult Toplevel() { return Binary(); }
ParseResult ParseToplevel() { return ParseBinary(); }
}; // namespace ExpressionParser
static ParseResult ParseComplexExpression(const std::string& str)