%token <ival>	INT%token <uval>	UINT%token <fval>	NUM%token <sval>	FUNC NAME%token <tval>	TIME%{package main //	Lgo tool yacc parse.yimport (	"clive/cmd"	"math"	"time") var (	debugYacc bool) func yprintf(x string, args ...interface{}) {	if debugYacc {		cmd.Dprintf(x, args...)	}} %} %union {	ival int64	uval uint64	fval float64	sval string	tval time.Time	vval interface{}} %left OR%left AND%left '=' EQN NEQ%left '<' '>' LE GE%left '+' '-'%left '*' '/' '%' '&' '|' SLEFT SRIGHT%nonassoc UMINUS FUNC '!' '^' %type <vval> expr %% toplvl:	expr	{		x := yylex.(*lex)		x.result = $1	} expr	:  expr '+' expr	{		$$ = add($1, $3)	}	| expr '-' expr	{		$$ = sub($1, $3)	}	| expr '*' expr	{		$$ = mul($1, $3)	}	| '-' expr %prec UMINUS	{		$$ = minus($2)	}	| expr '/' expr	{		$$ = div($1, $3)	}	| expr '%' expr	{		$$ = mod($1, $3)	}	| expr SLEFT expr	{		$$ = shiftleft($1, $3)	}	| expr SRIGHT expr	{		$$ = shiftright($1, $3)	}	| '(' expr ')'	{		$$ = $2	}	| FUNC expr	{		if f, ok := funcs[$1]; ok {			n := Nval($2)			$$ = f(n)		} else if v, err := fmtf($1, $2); err == nil {			$$ = v		} else if v, err := attr($1, $2); err == nil {			$$ = v		} else {			panic("unknown function")		}	}	| NUM	{		$$ = value($1)	}	| INT	{		$$ = value($1)	}	| UINT	{		$$ = value($1)	}	| NAME	{		$$ = value($1)	}	| TIME	{		$$ = value($1)	}	| expr '<' expr	{		$$ = value(cmp($1, $3) < 0)	}	| expr '>' expr	{		$$ = value(cmp($1, $3) > 0)	}	| expr LE expr	{		$$ = value(cmp($1, $3) <= 0)	}	| expr GE expr	{		$$ = value(cmp($1, $3) >= 0)	}	| expr '=' expr	{		$$ = value(cmp($1, $3) == 0)	}	| expr EQN expr	{		$$ = value(cmp($1, $3) == 0)	}	| expr NEQ expr	{		$$ = value(cmp($1, $3) != 0)	}	| expr AND expr	{		$$ = value(Bval($1) && Bval($3))	}	| expr OR expr	{		$$ = value(Bval($1) || Bval($3))	}	| expr '&' expr	{		$$ = value(Ival($1) & Ival($3))	}	| expr '|' expr	{		$$ = value(Ival($1) | Ival($3))	}	| '!' expr	{		$$ = value(! Bval($2))	}	| '^' expr	{		$$ = value(^ Ival($2))	}%% var funcs = map[string]func(float64)float64{	"abs": math.Abs,	"acos": math.Acos,	"acosh": math.Acosh,	"asin": math.Asin,	"asinh": math.Asinh,	"atan": math.Atan,	"atanh": math.Atanh,	"cbrt": math.Cbrt,	"cos": math.Cos,	"cosh": math.Cosh,	"exp": math.Exp,	"exp2": math.Exp2,	"floor": math.Floor,	"Γ": math.Gamma,	"log": math.Log,	"log10": math.Log10,	"log2": math.Log2,	"sin": math.Sin,	"sinh": math.Sinh,	"sqrt": math.Sqrt,	"tan": math.Tan,	"tanh": math.Tanh,	"trunc": math.Trunc,}