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#include "Parser.h"
class Parser
{
public:
Parser(IPLVector<Token>& tokens, const std::function<void()>& onError = {});
ExpressionPtr Parse();
private:
bool MatchOneOf(IPLVector<TokenType> types);
bool Match(TokenType type);
ExpressionPtr Unary();
ExpressionPtr LeftSideExpression();
ExpressionPtr SimpleExpression();
Token& Prev() { return m_Tokens[m_Current - 1]; }
std::function<void()> OnError;
unsigned m_Current;
IPLVector<Token> m_Tokens;
};
Parser::Parser(IPLVector<Token>& tokens, const std::function<void()>& onError)
: m_Tokens(tokens)
, OnError(onError)
, m_Current(0)
{
}
bool Parser::MatchOneOf(IPLVector<TokenType> types)
{
for (auto t : types)
{
if (t == m_Tokens[m_Current].Type)
{
++m_Current;
return true;
}
}
return false;
}
bool Parser::Match(TokenType type)
{
if (type == m_Tokens[m_Current].Type)
{
++m_Current;
return true;
}
return false;
}
ExpressionPtr Parser::SimpleExpression()
{
//SimpleExpression
// this
// | null
// | true
// | false
// | Number
// | String
// | Identifier
// | RegularExpression
// | ParenthesizedExpression
// | ArrayLiteral
if (Match({TokenType::Number}))
{
return IPLMakeSharePtr<LiteralExpression>(Prev().Number);
}
else if (Match({ TokenType::String }))
{
return IPLMakeSharePtr<LiteralExpression>(Prev().Lexeme);
}
else
{
// TODO implement
return ExpressionPtr();
}
}
ExpressionPtr Parser::LeftSideExpression()
{
//LeftSideExpression ->
// CallExpression
// | ShortNewExpression
// CallExpression ->
// PrimaryExpression
// | FullNewExpression
// | CallExpression MemberOperator
// | CallExpression Arguments
// FullNewExpression -> new FullNewSubexpression Arguments
// ShortNewExpression -> new ShortNewSubexpression
// FullNewSubexpression ->
// PrimaryExpressionnormal
// | FullNewExpression
// | FullNewSubexpression MemberOperator
// ShortNewSubexpression ->
// FullNewSubexpression
// | ShortNewExpression
// MemberOperator ->
// [Expressionnormal, allowIn]
//| .Identifier
// Arguments ->
// ()
// | (ArgumentList)
// ArgumentList ->
// AssignmentExpressionnormal, allowIn
// | ArgumentList, AssignmentExpressionnormal, allowIn
return SimpleExpression();
}
ExpressionPtr Parser::Unary()
{
//UnaryExpression
// PostfixExpression
// | delete LeftSideExpressionnormal
// | ++LeftSideExpressionnormal
// | --LeftSideExpressionnormal
// | void UnaryExpressionnormal
// | typeof UnaryExpressionnormal
// | +UnaryExpressionnormal
// | -UnaryExpressionnormal
// | ~UnaryExpressionnormal
// | !UnaryExpressionnormal
if (MatchOneOf({
TokenType::Delete,
TokenType::MinusMinus,
TokenType::PlusPlus,
}))
{
auto ls = LeftSideExpression();
auto suffix = false;
return IPLMakeSharePtr<UnaryExpression>(ls, Prev().Type, suffix);
}
else if (MatchOneOf({
TokenType::Void,
TokenType::Typeof,
TokenType::Plus,
TokenType::Minus,
TokenType::BitwiseNot,
TokenType::Bang,
}))
{
auto ls = Unary();
auto suffix = false;
return IPLMakeSharePtr<UnaryExpression>(ls, Prev().Type, suffix);
}
else
{
//PostfixExpression
// LeftSideExpression
// | LeftSideExpression++
// | LeftSideExpression--
auto leftSide = LeftSideExpression();
if (MatchOneOf({ TokenType::PlusPlus, TokenType::MinusMinus }))
{
auto suffix = true;
return IPLMakeSharePtr<UnaryExpression>(leftSide, Prev().Type, suffix);
}
return leftSide;
}
}
ExpressionPtr Parser::Parse()
{
// TODO implement full grammar
return Unary();
}
ExpressionPtr Parse(IPLVector<Token>& tokens, const std::function<void()>& onError)
{
Parser p(tokens, onError);
return p.Parse();
}
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