// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.

// control.go
package expr

// Preset control variables
const (
	ControlPreset        = "_preset"
	ControlLastResult    = "last"
	ControlBoolShortcut  = "_bool_shortcut"
	ControlSearchPath    = "_search_path"
	ControlParentContext = "_parent_context"
)

// Other control variables
const (
	control_export_all = "_export_all"
)

// Initial values
const (
	init_search_path = "~/.local/lib/go-pkg/expr:/usr/local/lib/go-pkg/expr:/usr/lib/go-pkg/expr"
)

func initDefaultVars(ctx ExprContext) {
	if _, exists := ctx.GetVar(ControlPreset); exists {
		return
	}
	ctx.SetVar(ControlPreset, true)
	ctx.SetVar(ControlBoolShortcut, true)
	ctx.SetVar(ControlSearchPath, init_search_path)
}

func getControlString(ctx ExprContext, name string) (s string, exists bool) {
	var v any
	if v, exists = ctx.GetVar(name); exists {
		s, exists = v.(string)
	}
	return
}