salix/for_tag.go

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/*
* Salix - Go templating engine
* Copyright (C) 2023 Elara Musayelyan
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
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package salix
import (
"reflect"
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"go.elara.ws/salix/ast"
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)
// forTag represents a #for tag within a Salix template
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type forTag struct{}
func (ft forTag) Run(tc *TagContext, block, args []ast.Node) error {
if len(args) == 0 || len(args) > 2 {
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return tc.PosError(tc.Tag, "invalid argument amount")
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}
var expr ast.Expr
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if len(args) == 1 {
expr2, ok := args[0].(ast.Expr)
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if !ok {
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return tc.PosError(args[0], "invalid argument type: %T (expected ast.Expr)", args[0])
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}
expr = expr2
} else if len(args) == 2 {
expr2, ok := args[1].(ast.Expr)
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if !ok {
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return tc.PosError(args[1], "invalid argument type: %T (expected ast.Expr)", args[1])
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}
expr = expr2
}
var vars []string
var in reflect.Value
if len(args) == 2 {
varName, ok := unwrap(args[0]).(ast.Ident)
if !ok {
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return tc.PosError(args[0], "invalid argument type: %T (expected ast.Ident)", expr.First)
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}
vars = append(vars, varName.Value)
}
varName, ok := unwrap(expr.First).(ast.Ident)
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if !ok {
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return tc.PosError(expr.First, "invalid argument type: %T (expected ast.Ident)", args[0])
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}
vars = append(vars, varName.Value)
if len(expr.Rest) != 1 {
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return tc.PosError(expr.First, "invalid expression (expected 1 element, got %d)", len(expr.Rest))
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}
rest := expr.Rest[0]
if rest.Operator.Value != "in" {
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return tc.PosError(expr.First, `invalid operator in expression (expected "in", got %q)`, rest.Operator.Value)
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}
val, err := tc.GetValue(rest, nil)
if err != nil {
return err
}
in = reflect.ValueOf(val)
switch in.Kind() {
case reflect.Slice, reflect.Array:
local := map[string]any{}
for i := 0; i < in.Len(); i++ {
if len(vars) == 1 {
local[vars[0]] = in.Index(i).Interface()
} else if len(vars) == 2 {
local[vars[0]] = i
local[vars[1]] = in.Index(i).Interface()
}
err = tc.Execute(block, local)
if err != nil {
return err
}
}
case reflect.Map:
local := map[string]any{}
iter := in.MapRange()
for iter.Next() {
if len(vars) == 1 {
local[vars[0]] = iter.Value().Interface()
} else if len(vars) == 2 {
local[vars[0]] = iter.Key().Interface()
local[vars[1]] = iter.Value().Interface()
}
err = tc.Execute(block, local)
if err != nil {
return err
}
}
}
return nil
}
func unwrap(n ast.Node) ast.Node {
if v, ok := n.(ast.Value); ok {
return v.Node
}
return n
}