expression

var (

	// LangEval is a custom GVal evaluator for business rules and facts conditions
	// It contains all supported custom functions (math, date, dateopendays, etc.)
	LangEval = gval.NewLanguage(
		gval.Full(),
		LangExprMath,
		LangEvalDate,
		LangEvalDateOpenDays,
		LangAdvancedInfix,
		LangEvalMap,
		LangEvalString,
		LangEvalSlice,
		LangEvalUrl,
	)

	// LangExprMath is a custom GVal evaluator for business rules and facts conditions
	// It contains custom functions related to math
	LangExprMath = gval.NewLanguage(
		gval.Full(),
		gval.Function("length", length),
		gval.Function("max", max),
		gval.Function("min", min),
		gval.Function("sum", sum),
		gval.Function("average", average),
		gval.Function("roundToDecimal", roundToDecimal),
		gval.Function("safeDivide", safeDivide),
	)

	// LangEvalDate is a custom GVal evaluator for business rules and facts conditions
	// It contains custom functions related to date
	LangEvalDate = gval.NewLanguage(
		gval.Full(),
		gval.Function("dayOfWeek", dayOfWeek),
		gval.Function("day", day),
		gval.Function("month", month),
		gval.Function("year", year),
		gval.Function("startOf", startOf),
		gval.Function("endOf", endOf),
		gval.Function("datemillis", dateToMillis),
		gval.Function("calendar_add", addDurationDays),
		gval.Function("calendar_delay", delayInDays),
		gval.Function("truncate_date", truncateDate),
		gval.Function("extract_from_date", extractFromDate),
		gval.Function("format_date", formatDate),
		gval.Function("get_value_current_day", getValueForCurrentDay),
		gval.Function("get_formatted_duration", getFormattedDuration),
	)

	// LangEvalDateOpenDays is a custom GVal evaluator for business rules and facts conditions
	// It contains custom functions related to date (opendays support)
	LangEvalDateOpenDays = gval.NewLanguage(
		gval.Full(),
		gval.Function("calendar_add_od", addDurationOpenDays),
		gval.Function("calendar_delay_od", delayInOpenDays),
	)

	// LangAdvancedInfix is a custom Gval evaluator for maps operations
	LangAdvancedInfix = gval.NewLanguage(
		gval.Full(),
		gval.InfixOperator("+", advancedAddition),
		gval.InfixOperator("-", advancedSubtraction),
		gval.InfixOperator("*", advancedMultiplication),
		gval.InfixOperator("/", advancedDivision),
	)

	LangEvalMap = gval.NewLanguage(
		gval.Full(),
		gval.Function("flatten_fact", flattenFact),
	)

	// LangEvalString is a custom GVal evaluator for handling char arrays (strings)
	LangEvalString = gval.NewLanguage(
		gval.Full(),
		gval.Function("replace", replace),
	)

	LangEvalSlice = gval.NewLanguage(
		gval.Full(),
		gval.Function("contains", contains),
	)

	LangEvalUrl = gval.NewLanguage(
		gval.Full(),
		gval.Function("url_encode", urlEncode),
		gval.Function("url_decode", urlDecode),
	)
)