expression.cpp File Reference

The parsing and evaluation of expressions. More...

#include <cassert>
#include <limits>
#include <iostream>
#include "expression.h"

Go to the source code of this file.

Enumerations
enum	mixal::ExprParseState { mixal::ExprParseState::START, mixal::ExprParseState::ATOMIC, mixal::ExprParseState::OPERATION, mixal::ExprParseState::END }

Functions
bool	mixal::isOperationFirst (char ch)
std::ostream &	mixal::operator<< (std::ostream &out, Operation operation)
std::ostream &	mixal::operator<< (std::ostream &out, const Expression &expression)

Detailed Description

The parsing and evaluation of expressions.

Definition in file expression.cpp.

Enumeration Type Documentation

ExprParseState

enum mixal::ExprParseState

strong

The states while parsing the expression.

EXPRESSION -> + EXPRESSION
            | - EXPRESSION
            | EXPRESSION OPERATOR EXPRESSION
            | ATOMIC
OPERATOR -> + | - | * | / | // | :
ATOMIC -> INTEGER
        | SYMBOL
        | *
INTEGER -> DIGIT
         | DIGIT INTEGER
SYMBOL -> ALPHA
        | DIGIT
        | ALPHS SYMBOL
        | DIGIT SYMBOL
DIGIT -> [0-9]
ALPHA -> [A-Z]

However, multiple signs like ++ or --- will be rejected as they are useless.

Definition at line 77 of file expression.cpp.

                          {
    START,      
    ATOMIC,     
    OPERATION,  
    END,        
};

Function Documentation

isOperationFirst()

bool mixal::isOperationFirst ( char  ch )

inline

Whether an operation can start with the given character.

Definition at line 85 of file expression.cpp.

                                      {
    return ch == '+' || ch == '-' || ch == '*' || ch == '/' || ch == ':';
}

References mixal::isOperationFirst().

Referenced by mixal::isOperationFirst(), and mixal::Expression::parse().

operator<<() [1/2]

std::ostream& mixal::operator<<	(	std::ostream &	out,
		const Expression &	expression
	)

Output the expression.

Definition at line 346 of file expression.cpp.

                                                                      {
    if (expression._atomics.size() > 0) {
        out << expression._atomics[0];
    }
    for (size_t i = 0; i < expression._operations.size(); ++i) {
        out << expression._operations[i];
        out << expression._atomics[i + 1];
    }
    return out;
}

References mixal::operator<<().

operator<<() [2/2]

std::ostream & mixal::operator<<	(	std::ostream &	out,
		Operation	operation
	)

Output the symbol of the operation.

Definition at line 335 of file expression.cpp.

                                                             {
    switch (operation) {
    case Operation::ADD: out << '+'; break;
    case Operation::SUBTRACT: out << '-'; break;
    case Operation::MULTIPLY: out << '*'; break;
    case Operation::FLOOR_DIV: out << '/'; break;
    case Operation::FIELD: out << ':'; break;
    }
    return out;
}

References mixal::operator<<().

Referenced by mixal::operator<<().