expr/helpers.go

88 lines
2.0 KiB
Go

// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.
// helpers.go
package expr
import (
"fmt"
"io"
"os"
"strings"
)
func EvalString(ctx ExprContext, source string) (result any, err error) {
var tree *ast
r := strings.NewReader(source)
scanner := NewScanner(r, DefaultTranslations())
parser := NewParser()
if tree, err = parser.Parse(scanner); err == nil {
result, err = tree.Eval(ctx)
}
return
}
type Arg struct {
Name string
Value any
}
func EvalStringA(source string, args ...Arg) (result any, err error) {
return EvalStringV(source, args)
}
func EvalStringV(source string, args []Arg) (result any, err error) {
ctx := NewSimpleStore()
for _, arg := range args {
if isFunc(arg.Value) {
if f, ok := arg.Value.(FuncTemplate); ok {
functor := NewGolangFunctor(f)
// ctx.RegisterFunc(arg.Name, functor, 0, -1)
ctx.RegisterFunc(arg.Name, functor, TypeAny, []ExprFuncParam{
NewFuncParamFlagDef(ParamValue, PfDefault|PfRepeat, 0),
})
} else {
err = fmt.Errorf("invalid function specification: %q", arg.Name)
}
} else if integer, ok := anyInteger(arg.Value); ok {
ctx.SetVar(arg.Name, integer)
} else if float, ok := anyFloat(arg.Value); ok {
ctx.SetVar(arg.Name, float)
} else if _, ok := arg.Value.(string); ok {
ctx.SetVar(arg.Name, arg.Value)
} else if _, ok := arg.Value.(bool); ok {
ctx.SetVar(arg.Name, arg.Value)
} else {
err = fmt.Errorf("unsupported type %T specified for item %q", arg.Value, arg.Name)
}
}
if err == nil {
result, err = EvalString(ctx, source)
}
return
}
func EvalStream(ctx ExprContext, r io.Reader) (result any, err error) {
var tree *ast
scanner := NewScanner(r, DefaultTranslations())
parser := NewParser()
if tree, err = parser.Parse(scanner); err == nil {
result, err = tree.Eval(ctx)
}
return
}
func EvalFile(ctx ExprContext, filePath string) (result any, err error) {
var fh *os.File
if fh, err = os.Open(filePath); err != nil {
return nil, err
}
defer fh.Close()
result, err = EvalStream(ctx, fh)
return
}