dolphin/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp

746 lines
18 KiB
C++

// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
#include <cassert>
#include <cmath>
#include <iostream>
#include <memory>
#include <regex>
#include <string>
#include <utility>
#include <vector>
#include "Common/Common.h"
#include "Common/StringUtil.h"
#include "InputCommon/ControlReference/ExpressionParser.h"
#include "InputCommon/ControlReference/FunctionExpression.h"
namespace ciface::ExpressionParser
{
using namespace ciface::Core;
Token::Token(TokenType type_) : type(type_)
{
}
Token::Token(TokenType type_, std::string data_) : type(type_), data(std::move(data_))
{
}
bool Token::IsBinaryOperator() const
{
return type >= TOK_BINARY_OPS_BEGIN && type < TOK_BINARY_OPS_END;
}
Lexer::Lexer(std::string expr_) : expr(std::move(expr_))
{
it = expr.begin();
}
std::string Lexer::FetchDelimString(char delim)
{
const std::string result = FetchCharsWhile([delim](char c) { return c != delim; });
if (it != expr.end())
++it;
return result;
}
std::string Lexer::FetchWordChars()
{
// Valid word characters:
std::regex rx(R"([a-z\d_])", std::regex_constants::icase);
return FetchCharsWhile([&rx](char c) { return std::regex_match(std::string(1, c), rx); });
}
Token Lexer::GetDelimitedLiteral()
{
return Token(TOK_LITERAL, FetchDelimString('\''));
}
Token Lexer::GetVariable()
{
return Token(TOK_VARIABLE, FetchWordChars());
}
Token Lexer::GetFullyQualifiedControl()
{
return Token(TOK_CONTROL, FetchDelimString('`'));
}
Token Lexer::GetBareword(char first_char)
{
return Token(TOK_BAREWORD, first_char + FetchWordChars());
}
Token Lexer::GetRealLiteral(char first_char)
{
std::string value;
value += first_char;
value += FetchCharsWhile([](char c) { return isdigit(c, std::locale::classic()) || ('.' == c); });
if (std::regex_match(value, std::regex(R"(\d+(\.\d+)?)")))
return Token(TOK_LITERAL, value);
return Token(TOK_INVALID);
}
Token Lexer::PeekToken()
{
const auto old_it = it;
const auto tok = NextToken();
it = old_it;
return tok;
}
Token Lexer::NextToken()
{
if (it == expr.end())
return Token(TOK_EOF);
char c = *it++;
switch (c)
{
case ' ':
case '\t':
case '\n':
case '\r':
return Token(TOK_WHITESPACE);
case '(':
return Token(TOK_LPAREN);
case ')':
return Token(TOK_RPAREN);
case '&':
return Token(TOK_AND);
case '|':
return Token(TOK_OR);
case '!':
return Token(TOK_NOT);
case '+':
return Token(TOK_ADD);
case '-':
return Token(TOK_SUB);
case '*':
return Token(TOK_MUL);
case '/':
return Token(TOK_DIV);
case '%':
return Token(TOK_MOD);
case '=':
return Token(TOK_ASSIGN);
case '<':
return Token(TOK_LTHAN);
case '>':
return Token(TOK_GTHAN);
case ',':
return Token(TOK_COMMA);
case '^':
return Token(TOK_XOR);
case '\'':
return GetDelimitedLiteral();
case '$':
return GetVariable();
case '`':
return GetFullyQualifiedControl();
default:
if (isalpha(c, std::locale::classic()))
return GetBareword(c);
else if (isdigit(c, std::locale::classic()))
return GetRealLiteral(c);
else
return Token(TOK_INVALID);
}
}
ParseStatus Lexer::Tokenize(std::vector<Token>& tokens)
{
while (true)
{
const std::size_t string_position = it - expr.begin();
Token tok = NextToken();
tok.string_position = string_position;
tok.string_length = it - expr.begin();
// Handle /* */ style comments.
if (tok.type == TOK_DIV && PeekToken().type == TOK_MUL)
{
const auto end_of_comment = expr.find("*/", it - expr.begin());
if (end_of_comment == std::string::npos)
return ParseStatus::SyntaxError;
tok.type = TOK_COMMENT;
tok.string_length = end_of_comment + 4;
it = expr.begin() + end_of_comment + 2;
}
tokens.push_back(tok);
if (tok.type == TOK_INVALID)
return ParseStatus::SyntaxError;
if (tok.type == TOK_EOF)
break;
}
return ParseStatus::Successful;
}
class ControlExpression : public Expression
{
public:
// Keep a shared_ptr to the device so the control pointer doesn't become invalid.
std::shared_ptr<Device> m_device;
explicit ControlExpression(ControlQualifier qualifier_) : qualifier(qualifier_) {}
ControlState GetValue() const override
{
if (!input)
return 0.0;
// Note: Inputs may return negative values in situations where opposing directions are
// activated. We clamp off the negative values here.
// FYI: Clamping values greater than 1.0 is purposely not done to support unbounded values in
// the future. (e.g. raw accelerometer/gyro data)
return std::max(0.0, input->GetState());
}
void SetValue(ControlState value) override
{
if (output)
output->SetState(value);
}
int CountNumControls() const override { return (input || output) ? 1 : 0; }
void UpdateReferences(ControlEnvironment& env) override
{
m_device = env.FindDevice(qualifier);
input = env.FindInput(qualifier);
output = env.FindOutput(qualifier);
}
private:
ControlQualifier qualifier;
Device::Input* input = nullptr;
Device::Output* output = nullptr;
};
class BinaryExpression : public Expression
{
public:
TokenType op;
std::unique_ptr<Expression> lhs;
std::unique_ptr<Expression> rhs;
BinaryExpression(TokenType op_, std::unique_ptr<Expression>&& lhs_,
std::unique_ptr<Expression>&& rhs_)
: op(op_), lhs(std::move(lhs_)), rhs(std::move(rhs_))
{
}
ControlState GetValue() const override
{
switch (op)
{
case TOK_AND:
return std::min(lhs->GetValue(), rhs->GetValue());
case TOK_OR:
return std::max(lhs->GetValue(), rhs->GetValue());
case TOK_ADD:
return lhs->GetValue() + rhs->GetValue();
case TOK_SUB:
return lhs->GetValue() - rhs->GetValue();
case TOK_MUL:
return lhs->GetValue() * rhs->GetValue();
case TOK_DIV:
{
const ControlState result = lhs->GetValue() / rhs->GetValue();
return std::isinf(result) ? 0.0 : result;
}
case TOK_MOD:
{
const ControlState result = std::fmod(lhs->GetValue(), rhs->GetValue());
return std::isnan(result) ? 0.0 : result;
}
case TOK_ASSIGN:
{
lhs->SetValue(rhs->GetValue());
return lhs->GetValue();
}
case TOK_LTHAN:
return lhs->GetValue() < rhs->GetValue();
case TOK_GTHAN:
return lhs->GetValue() > rhs->GetValue();
case TOK_COMMA:
{
// Eval and discard lhs:
lhs->GetValue();
return rhs->GetValue();
}
case TOK_XOR:
{
const auto lval = lhs->GetValue();
const auto rval = rhs->GetValue();
return std::max(std::min(1 - lval, rval), std::min(lval, 1 - rval));
}
default:
assert(false);
return 0;
}
}
void SetValue(ControlState value) override
{
// Don't do anything special with the op we have.
// Treat "A & B" the same as "A | B".
lhs->SetValue(value);
rhs->SetValue(value);
}
int CountNumControls() const override
{
return lhs->CountNumControls() + rhs->CountNumControls();
}
void UpdateReferences(ControlEnvironment& env) override
{
lhs->UpdateReferences(env);
rhs->UpdateReferences(env);
}
};
class LiteralExpression : public Expression
{
public:
void SetValue(ControlState) override
{
// Do nothing.
}
int CountNumControls() const override { return 1; }
void UpdateReferences(ControlEnvironment&) override
{
// Nothing needed.
}
protected:
virtual std::string GetName() const = 0;
};
class LiteralReal : public LiteralExpression
{
public:
LiteralReal(ControlState value) : m_value(value) {}
ControlState GetValue() const override { return m_value; }
std::string GetName() const override { return ValueToString(m_value); }
private:
const ControlState m_value{};
};
ParseResult MakeLiteralExpression(Token token)
{
ControlState val{};
if (TryParse(token.data, &val))
return ParseResult::MakeSuccessfulResult(std::make_unique<LiteralReal>(val));
else
return ParseResult::MakeErrorResult(token, _trans("Invalid literal."));
}
class VariableExpression : public Expression
{
public:
VariableExpression(std::string name) : m_name(name) {}
ControlState GetValue() const override { return *m_value_ptr; }
void SetValue(ControlState value) override { *m_value_ptr = value; }
int CountNumControls() const override { return 1; }
void UpdateReferences(ControlEnvironment& env) override
{
m_value_ptr = env.GetVariablePtr(m_name);
}
protected:
const std::string m_name;
ControlState* m_value_ptr{};
};
// This class proxies all methods to its either left-hand child if it has bound controls, or its
// right-hand child. Its intended use is for supporting old-style barewords expressions.
class CoalesceExpression : public Expression
{
public:
CoalesceExpression(std::unique_ptr<Expression>&& lhs, std::unique_ptr<Expression>&& rhs)
: m_lhs(std::move(lhs)), m_rhs(std::move(rhs))
{
}
ControlState GetValue() const override { return GetActiveChild()->GetValue(); }
void SetValue(ControlState value) override { GetActiveChild()->SetValue(value); }
int CountNumControls() const override { return GetActiveChild()->CountNumControls(); }
void UpdateReferences(ControlEnvironment& env) override
{
m_lhs->UpdateReferences(env);
m_rhs->UpdateReferences(env);
}
private:
const std::unique_ptr<Expression>& GetActiveChild() const
{
return m_lhs->CountNumControls() > 0 ? m_lhs : m_rhs;
}
std::unique_ptr<Expression> m_lhs;
std::unique_ptr<Expression> m_rhs;
};
std::shared_ptr<Device> ControlEnvironment::FindDevice(ControlQualifier qualifier) const
{
if (qualifier.has_device)
return container.FindDevice(qualifier.device_qualifier);
else
return container.FindDevice(default_device);
}
Device::Input* ControlEnvironment::FindInput(ControlQualifier qualifier) const
{
const std::shared_ptr<Device> device = FindDevice(qualifier);
if (!device)
return nullptr;
return device->FindInput(qualifier.control_name);
}
Device::Output* ControlEnvironment::FindOutput(ControlQualifier qualifier) const
{
const std::shared_ptr<Device> device = FindDevice(qualifier);
if (!device)
return nullptr;
return device->FindOutput(qualifier.control_name);
}
ControlState* ControlEnvironment::GetVariablePtr(const std::string& name)
{
return &m_variables[name];
}
ParseResult ParseResult::MakeEmptyResult()
{
ParseResult result;
result.status = ParseStatus::EmptyExpression;
return result;
}
ParseResult ParseResult::MakeSuccessfulResult(std::unique_ptr<Expression>&& expr)
{
ParseResult result;
result.status = ParseStatus::Successful;
result.expr = std::move(expr);
return result;
}
ParseResult ParseResult::MakeErrorResult(Token token, std::string description)
{
ParseResult result;
result.status = ParseStatus::SyntaxError;
result.token = std::move(token);
result.description = std::move(description);
return result;
}
class Parser
{
public:
explicit Parser(const std::vector<Token>& tokens_) : tokens(tokens_) { m_it = tokens.begin(); }
ParseResult Parse()
{
ParseResult result = ParseToplevel();
if (ParseStatus::Successful != result.status)
return result;
if (Peek().type == TOK_EOF)
return result;
return ParseResult::MakeErrorResult(Peek(), _trans("Expected end of expression."));
}
private:
const std::vector<Token>& tokens;
std::vector<Token>::const_iterator m_it;
Token Chew()
{
const Token tok = Peek();
if (TOK_EOF != tok.type)
++m_it;
return tok;
}
Token Peek() { return *m_it; }
bool Expects(TokenType type)
{
Token tok = Chew();
return tok.type == type;
}
ParseResult ParseFunctionArguments(const std::string_view& func_name,
std::unique_ptr<FunctionExpression>&& func,
const Token& func_tok)
{
std::vector<std::unique_ptr<Expression>> args;
if (TOK_LPAREN != Peek().type)
{
// Single argument with no parens (useful for unary ! function)
const auto tok = Chew();
auto arg = ParseAtom(tok);
if (ParseStatus::Successful != arg.status)
return arg;
args.emplace_back(std::move(arg.expr));
}
else
{
// Chew the L-Paren
Chew();
// Check for empty argument list:
if (TOK_RPAREN == Peek().type)
{
Chew();
}
else
{
while (true)
{
// Read one argument.
// Grab an expression, but stop at comma.
auto arg = ParseBinary(BinaryOperatorPrecedence(TOK_COMMA));
if (ParseStatus::Successful != arg.status)
return arg;
args.emplace_back(std::move(arg.expr));
// Right paren is the end of our arguments.
const Token tok = Chew();
if (TOK_RPAREN == tok.type)
break;
// Comma before the next argument.
if (TOK_COMMA != tok.type)
return ParseResult::MakeErrorResult(tok, _trans("Expected comma."));
};
}
}
const auto argument_validation = func->SetArguments(std::move(args));
if (std::holds_alternative<FunctionExpression::ExpectedArguments>(argument_validation))
{
const auto text = std::string(func_name) + '(' +
std::get<FunctionExpression::ExpectedArguments>(argument_validation).text +
')';
return ParseResult::MakeErrorResult(func_tok, _trans("Expected arguments: " + text));
}
return ParseResult::MakeSuccessfulResult(std::move(func));
}
ParseResult ParseAtom(const Token& tok)
{
switch (tok.type)
{
case TOK_BAREWORD:
{
auto func = MakeFunctionExpression(tok.data);
if (!func)
{
// Invalid function, interpret this as a bareword control.
Token control_tok(tok);
control_tok.type = TOK_CONTROL;
return ParseAtom(control_tok);
}
return ParseFunctionArguments(tok.data, std::move(func), tok);
}
case TOK_CONTROL:
{
ControlQualifier cq;
cq.FromString(tok.data);
return ParseResult::MakeSuccessfulResult(std::make_unique<ControlExpression>(cq));
}
case TOK_NOT:
{
return ParseFunctionArguments("not", MakeFunctionExpression("not"), tok);
}
case TOK_LITERAL:
{
return MakeLiteralExpression(tok);
}
case TOK_VARIABLE:
{
return ParseResult::MakeSuccessfulResult(std::make_unique<VariableExpression>(tok.data));
}
case TOK_LPAREN:
{
return ParseParens();
}
case TOK_SUB:
{
// An atom was expected but we got a subtraction symbol.
// Interpret it as a unary minus function.
return ParseFunctionArguments("minus", MakeFunctionExpression("minus"), tok);
}
default:
{
return ParseResult::MakeErrorResult(tok, _trans("Expected start of expression."));
}
}
}
static int BinaryOperatorPrecedence(TokenType type)
{
switch (type)
{
case TOK_MUL:
case TOK_DIV:
case TOK_MOD:
return 1;
case TOK_ADD:
case TOK_SUB:
return 2;
case TOK_GTHAN:
case TOK_LTHAN:
return 3;
case TOK_AND:
return 4;
case TOK_XOR:
return 5;
case TOK_OR:
return 6;
case TOK_ASSIGN:
return 7;
case TOK_COMMA:
return 8;
default:
assert(false);
return 0;
}
}
ParseResult ParseBinary(int precedence = 999)
{
ParseResult lhs = ParseAtom(Chew());
if (lhs.status == ParseStatus::SyntaxError)
return lhs;
std::unique_ptr<Expression> expr = std::move(lhs.expr);
// TODO: handle LTR/RTL associativity?
while (Peek().IsBinaryOperator() && BinaryOperatorPrecedence(Peek().type) < precedence)
{
const Token tok = Chew();
ParseResult rhs = ParseBinary(BinaryOperatorPrecedence(tok.type));
if (rhs.status == ParseStatus::SyntaxError)
{
return rhs;
}
expr = std::make_unique<BinaryExpression>(tok.type, std::move(expr), std::move(rhs.expr));
}
return ParseResult::MakeSuccessfulResult(std::move(expr));
}
ParseResult ParseParens()
{
// lparen already chewed
ParseResult result = ParseToplevel();
if (result.status != ParseStatus::Successful)
return result;
const auto rparen = Chew();
if (rparen.type != TOK_RPAREN)
{
return ParseResult::MakeErrorResult(rparen, _trans("Expected closing paren."));
}
return result;
}
ParseResult ParseToplevel() { return ParseBinary(); }
}; // namespace ExpressionParser
ParseResult ParseTokens(const std::vector<Token>& tokens)
{
return Parser(tokens).Parse();
}
static ParseResult ParseComplexExpression(const std::string& str)
{
Lexer l(str);
std::vector<Token> tokens;
const ParseStatus tokenize_status = l.Tokenize(tokens);
if (tokenize_status != ParseStatus::Successful)
return ParseResult::MakeErrorResult(Token(TOK_INVALID), _trans("Tokenizing failed."));
RemoveInertTokens(&tokens);
return ParseTokens(tokens);
}
void RemoveInertTokens(std::vector<Token>* tokens)
{
tokens->erase(std::remove_if(tokens->begin(), tokens->end(),
[](const Token& tok) {
return tok.type == TOK_COMMENT || tok.type == TOK_WHITESPACE;
}),
tokens->end());
}
static std::unique_ptr<Expression> ParseBarewordExpression(const std::string& str)
{
ControlQualifier qualifier;
qualifier.control_name = str;
qualifier.has_device = false;
return std::make_unique<ControlExpression>(qualifier);
}
ParseResult ParseExpression(const std::string& str)
{
if (StripSpaces(str).empty())
return ParseResult::MakeEmptyResult();
auto bareword_expr = ParseBarewordExpression(str);
ParseResult complex_result = ParseComplexExpression(str);
if (complex_result.status != ParseStatus::Successful)
{
// This is a bit odd.
// Return the error status of the complex expression with the fallback barewords expression.
complex_result.expr = std::move(bareword_expr);
return complex_result;
}
complex_result.expr = std::make_unique<CoalesceExpression>(std::move(bareword_expr),
std::move(complex_result.expr));
return complex_result;
}
} // namespace ciface::ExpressionParser