salix/for_tag.go

107 lines
2.3 KiB
Go

package salix
import (
"reflect"
"go.elara.ws/salix/ast"
)
// forTag represents a #for tag within a Salix template
type forTag struct{}
func (ft forTag) Run(tc *TagContext, block, args []ast.Node) error {
if len(args) == 0 || len(args) > 2 {
return tc.PosError(tc.Tag, "invalid argument amount")
}
var expr ast.Expr
if len(args) == 1 {
expr2, ok := args[0].(ast.Expr)
if !ok {
return tc.PosError(args[0], "invalid argument type: %T (expected ast.Expr)", args[0])
}
expr = expr2
} else if len(args) == 2 {
expr2, ok := args[1].(ast.Expr)
if !ok {
return tc.PosError(args[1], "invalid argument type: %T (expected ast.Expr)", args[1])
}
expr = expr2
}
var vars []string
var in reflect.Value
if len(args) == 2 {
varName, ok := unwrap(args[0]).(ast.Ident)
if !ok {
return tc.PosError(args[0], "invalid argument type: %T (expected ast.Ident)", expr.First)
}
vars = append(vars, varName.Value)
}
varName, ok := unwrap(expr.First).(ast.Ident)
if !ok {
return tc.PosError(expr.First, "invalid argument type: %T (expected ast.Ident)", args[0])
}
vars = append(vars, varName.Value)
if len(expr.Rest) != 1 {
return tc.PosError(expr.First, "invalid expression (expected 1 element, got %d)", len(expr.Rest))
}
rest := expr.Rest[0]
if rest.Operator.Value != "in" {
return tc.PosError(expr.First, `invalid operator in expression (expected "in", got %q)`, rest.Operator.Value)
}
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
}