expr/builtin-iterator.go

105 lines
2.5 KiB
Go

// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.
// builtin-iterator.go
package expr
import (
"fmt"
"io"
)
const (
iterParamOperator = "operator"
iterParamVars = "vars"
iterVarStatus = "status"
)
func parseRunArgs(localCtx ExprContext, args map[string]any) (it Iterator, op Functor, err error) {
var ok bool
if it, ok = args[ParamIterator].(Iterator); !ok {
err = fmt.Errorf("paramter %q must be an iterator, passed %v [%s]", ParamIterator, args[ParamIterator], TypeName(args[ParamIterator]))
return
}
if op, ok = args[iterParamOperator].(Functor); !ok && args[iterParamOperator] != nil {
err = fmt.Errorf("paramter %q must be a function, passed %v [%s]", iterParamOperator, args[iterParamOperator], TypeName(args[iterParamOperator]))
return
}
var vars *DictType
if vars, ok = args[iterParamVars].(*DictType); !ok && args[iterParamVars] != nil {
err = fmt.Errorf("paramter %q must be a dictionary, passed %v [%s]", iterParamVars, args[iterParamVars], TypeName(args[iterParamVars]))
return
}
if vars != nil {
for key, value := range *vars {
var varName string
if varName, ok = key.(string); ok {
localCtx.UnsafeSetVar(varName, value)
}
}
}
return
}
func runFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
var it Iterator
var ok bool
var op Functor
var v any
var usingDefaultOp = false
var params map[string]any
var item any
localCtx := ctx.Clone()
localCtx.UnsafeSetVar(iterVarStatus, nil)
if it, op, err = parseRunArgs(localCtx, args); err != nil {
return
} else if op == nil {
op = NewGolangFunctor(printLnFunc)
usingDefaultOp = true
}
for item, err = it.Next(); err == nil; item, err = it.Next() {
if usingDefaultOp {
params = map[string]any{ParamItem: []any{item}}
} else {
params = map[string]any{ParamIndex: it.Index(), ParamItem: item}
}
if v, err = op.InvokeNamed(localCtx, iterParamOperator, params); err != nil {
break
} else {
var success bool
if success, ok = ToBool(v); !success || !ok {
break
}
}
}
if err == io.EOF {
err = nil
}
if err == nil {
result, _ = localCtx.GetVar(iterVarStatus)
}
return
}
func ImportIterFuncs(ctx ExprContext) {
ctx.RegisterFunc("run", NewGolangFunctor(runFunc), TypeAny, []ExprFuncParam{
NewFuncParam(ParamIterator),
NewFuncParamFlag(iterParamOperator, PfOptional),
NewFuncParamFlag(iterParamVars, PfOptional),
})
}
func init() {
RegisterBuiltinModule("iterator", ImportIterFuncs, "Iterator helper functions")
}