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package govaluate
/*
Represents the valid symbols for operators.
*/
type OperatorSymbol int
const (
VALUE OperatorSymbol = iota
LITERAL
NOOP
EQ
NEQ
GT
LT
GTE
LTE
REQ
NREQ
IN
AND
OR
PLUS
MINUS
BITWISE_AND
BITWISE_OR
BITWISE_XOR
BITWISE_LSHIFT
BITWISE_RSHIFT
MULTIPLY
DIVIDE
MODULUS
EXPONENT
NEGATE
INVERT
BITWISE_NOT
TERNARY_TRUE
TERNARY_FALSE
COALESCE
FUNCTIONAL
ACCESS
SEPARATE
)
type operatorPrecedence int
const (
noopPrecedence operatorPrecedence = iota
valuePrecedence
functionalPrecedence
prefixPrecedence
exponentialPrecedence
additivePrecedence
bitwisePrecedence
bitwiseShiftPrecedence
multiplicativePrecedence
comparatorPrecedence
ternaryPrecedence
logicalAndPrecedence
logicalOrPrecedence
separatePrecedence
)
func findOperatorPrecedenceForSymbol(symbol OperatorSymbol) operatorPrecedence {
switch symbol {
case NOOP:
return noopPrecedence
case VALUE:
return valuePrecedence
case EQ:
fallthrough
case NEQ:
fallthrough
case GT:
fallthrough
case LT:
fallthrough
case GTE:
fallthrough
case LTE:
fallthrough
case REQ:
fallthrough
case NREQ:
fallthrough
case IN:
return comparatorPrecedence
case AND:
return logicalAndPrecedence
case OR:
return logicalOrPrecedence
case BITWISE_AND:
fallthrough
case BITWISE_OR:
fallthrough
case BITWISE_XOR:
return bitwisePrecedence
case BITWISE_LSHIFT:
fallthrough
case BITWISE_RSHIFT:
return bitwiseShiftPrecedence
case PLUS:
fallthrough
case MINUS:
return additivePrecedence
case MULTIPLY:
fallthrough
case DIVIDE:
fallthrough
case MODULUS:
return multiplicativePrecedence
case EXPONENT:
return exponentialPrecedence
case BITWISE_NOT:
fallthrough
case NEGATE:
fallthrough
case INVERT:
return prefixPrecedence
case COALESCE:
fallthrough
case TERNARY_TRUE:
fallthrough
case TERNARY_FALSE:
return ternaryPrecedence
case ACCESS:
fallthrough
case FUNCTIONAL:
return functionalPrecedence
case SEPARATE:
return separatePrecedence
}
return valuePrecedence
}
/*
Map of all valid comparators, and their string equivalents.
Used during parsing of expressions to determine if a symbol is, in fact, a comparator.
Also used during evaluation to determine exactly which comparator is being used.
*/
var comparatorSymbols = map[string]OperatorSymbol{
"==": EQ,
"!=": NEQ,
">": GT,
">=": GTE,
"<": LT,
"<=": LTE,
"=~": REQ,
"!~": NREQ,
"in": IN,
}
var logicalSymbols = map[string]OperatorSymbol{
"&&": AND,
"||": OR,
}
var bitwiseSymbols = map[string]OperatorSymbol{
"^": BITWISE_XOR,
"&": BITWISE_AND,
"|": BITWISE_OR,
}
var bitwiseShiftSymbols = map[string]OperatorSymbol{
">>": BITWISE_RSHIFT,
"<<": BITWISE_LSHIFT,
}
var additiveSymbols = map[string]OperatorSymbol{
"+": PLUS,
"-": MINUS,
}
var multiplicativeSymbols = map[string]OperatorSymbol{
"*": MULTIPLY,
"/": DIVIDE,
"%": MODULUS,
}
var exponentialSymbolsS = map[string]OperatorSymbol{
"**": EXPONENT,
}
var prefixSymbols = map[string]OperatorSymbol{
"-": NEGATE,
"!": INVERT,
"~": BITWISE_NOT,
}
var ternarySymbols = map[string]OperatorSymbol{
"?": TERNARY_TRUE,
":": TERNARY_FALSE,
"??": COALESCE,
}
// this is defined separately from additiveSymbols et al because it's needed for parsing, not stage planning.
var modifierSymbols = map[string]OperatorSymbol{
"+": PLUS,
"-": MINUS,
"*": MULTIPLY,
"/": DIVIDE,
"%": MODULUS,
"**": EXPONENT,
"&": BITWISE_AND,
"|": BITWISE_OR,
"^": BITWISE_XOR,
">>": BITWISE_RSHIFT,
"<<": BITWISE_LSHIFT,
}
var separatorSymbols = map[string]OperatorSymbol{
",": SEPARATE,
}
/*
Returns true if this operator is contained by the given array of candidate symbols.
False otherwise.
*/
func (this OperatorSymbol) IsModifierType(candidate []OperatorSymbol) bool {
for _, symbolType := range candidate {
if this == symbolType {
return true
}
}
return false
}
/*
Generally used when formatting type check errors.
We could store the stringified symbol somewhere else and not require a duplicated codeblock to translate
OperatorSymbol to string, but that would require more memory, and another field somewhere.
Adding operators is rare enough that we just stringify it here instead.
*/
func (this OperatorSymbol) String() string {
switch this {
case NOOP:
return "NOOP"
case VALUE:
return "VALUE"
case EQ:
return "="
case NEQ:
return "!="
case GT:
return ">"
case LT:
return "<"
case GTE:
return ">="
case LTE:
return "<="
case REQ:
return "=~"
case NREQ:
return "!~"
case AND:
return "&&"
case OR:
return "||"
case IN:
return "in"
case BITWISE_AND:
return "&"
case BITWISE_OR:
return "|"
case BITWISE_XOR:
return "^"
case BITWISE_LSHIFT:
return "<<"
case BITWISE_RSHIFT:
return ">>"
case PLUS:
return "+"
case MINUS:
return "-"
case MULTIPLY:
return "*"
case DIVIDE:
return "/"
case MODULUS:
return "%"
case EXPONENT:
return "**"
case NEGATE:
return "-"
case INVERT:
return "!"
case BITWISE_NOT:
return "~"
case TERNARY_TRUE:
return "?"
case TERNARY_FALSE:
return ":"
case COALESCE:
return "??"
}
return ""
}
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