forked from maja42/goval
/
parser.go.y
143 lines (124 loc) · 4.19 KB
/
parser.go.y
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%{
package internal
%}
%union {
token Token
expr interface{}
exprList []interface{}
exprMap map[string]interface{}
}
%start program
%type<expr> program
%type<expr> expr
%type<expr> literal
%type<expr> math
%type<expr> logic
%type<expr> bitManipulation
%type<expr> varAccess
%type<exprList> exprList
%type<exprMap> exprMap
%token<token> LITERAL_NIL // nil
%token<token> LITERAL_BOOL // true false
%token<token> LITERAL_NUMBER // 42 4.2 4e2 4.2e2
%token<token> LITERAL_STRING // "text" 'text'
%token<token> IDENT
%token<token> AND // &&
%token<token> OR // ||
%token<token> EQL // ==
%token<token> NEQ // !=
%token<token> LSS // <
%token<token> GTR // >
%token<token> LEQ // <=
%token<token> GEQ // >=
%token<token> SHL // <<
%token<token> SHR // >>
%token<token> BIT_NOT // ~
%token<token> IN // in
/* Operator precedence is taken from C/C++: http://en.cppreference.com/w/c/language/operator_precedence */
%left OR
%left AND
%left '|'
%left '^'
%left '&'
%left EQL NEQ
%left LSS LEQ GTR GEQ
%left SHL SHR
%left '+' '-'
%left '*' '/' '%'
%right '!' BIT_NOT
%left IN
%left '.' '[' ']'
%%
program
: expr
{
$$ = $1
yylex.(*Lexer).result = $$
}
;
expr
: literal
| math
| logic
| bitManipulation
| varAccess
| '(' expr ')' { $$ = $2 }
| IDENT '(' ')' { $$ = callFunction(yylex.(*Lexer).functions, $1.literal, []interface{}{}) }
| IDENT '(' exprList ')' { $$ = callFunction(yylex.(*Lexer).functions, $1.literal, $3) }
;
literal
: LITERAL_NIL { $$ = nil }
| LITERAL_BOOL { $$ = $1.value }
| LITERAL_NUMBER { $$ = $1.value }
| LITERAL_STRING { $$ = $1.value }
| '[' ']' { $$ = []interface{}{} }
| '[' exprList ']' { $$ = $2 }
| '{' '}' { $$ = map[string]interface{}{} }
| '{' exprMap '}' { $$ = $2 }
;
math
: '-' expr %prec '!' { $$ = unaryMinus($2) } /* unary minus has higher precedence */
| expr '+' expr { $$ = add($1, $3) }
| expr '-' expr { $$ = sub($1, $3) }
| expr '*' expr { $$ = mul($1, $3) }
| expr '/' expr { $$ = div($1, $3) }
| expr '%' expr { $$ = mod($1, $3) }
;
logic
: '!' expr { $$ = !asBool($2) }
| expr EQL expr { $$ = deepEqual($1, $3) }
| expr NEQ expr { $$ = !deepEqual($1, $3) }
| expr LSS expr { $$ = compare($1, $3, "<") }
| expr GTR expr { $$ = compare($1, $3, ">") }
| expr LEQ expr { $$ = compare($1, $3, "<=") }
| expr GEQ expr { $$ = compare($1, $3, ">=") }
| expr AND expr { left := asBool($1); right := asBool($3); $$ = left && right }
| expr OR expr { left := asBool($1); right := asBool($3); $$ = left || right }
;
bitManipulation
: expr '|' expr { $$ = asInteger($1) | asInteger($3) }
| expr '&' expr { $$ = asInteger($1) & asInteger($3) }
| expr '^' expr { $$ = asInteger($1) ^ asInteger($3) }
| expr SHL expr { l := asInteger($1); r := asInteger($3); if r >= 0 { $$ = l << uint(r) } else {$$ = l >> uint(-r)} }
| expr SHR expr { l := asInteger($1); r := asInteger($3); if r >= 0 { $$ = l >> uint(r) } else {$$ = l << uint(-r)} }
| BIT_NOT expr { $$ = ^asInteger($2) }
;
varAccess
: IDENT { $$ = accessVar(yylex.(*Lexer).variables, $1.literal) }
| expr '.' IDENT { $$ = accessField($1, $3.literal) }
| expr '[' expr ']' { $$ = accessField($1, $3) }
| expr IN expr { $$ = arrayContains($3, $1) }
| expr '[' expr ':' expr ']' { $$ = slice($1, $3, $5) }
| expr '[' ':' expr ']' { $$ = slice($1, nil, $4) }
| expr '[' expr ':' ']' { $$ = slice($1, $3, nil) }
| expr '[' ':' ']' { $$ = slice($1, nil, nil) }
;
exprList
: expr { $$ = []interface{}{$1} }
| exprList ',' expr { $$ = append($1, $3) }
;
exprMap
: expr ':' expr { $$ = make(map[string]interface{}); $$[asObjectKey($1)] = $3 }
| exprMap ',' expr ':' expr { $$ = addObjectMember($1, $3, $5) }
;
%%