formulajs_registry.go

package formula

import (
	"bufio"
	"bytes"
	_ "embed"
	"strings"
	"sync"
)

//go:embed formulajs_catalog.txt
var formulajsCatalogRaw []byte

var (
	builtinRegistryMemo map[string]builtinFunc
	builtinRegistryOnce sync.Once
)

func builtinRegistry() map[string]builtinFunc {
	builtinRegistryOnce.Do(func() {
		builtinRegistryMemo = buildBuiltinRegistry()
	})
	return builtinRegistryMemo
}

func buildBuiltinRegistry() map[string]builtinFunc {
	m := make(map[string]builtinFunc)

	put := func(name string, fn builtinFunc) {
		n := strings.ToLower(strings.TrimSpace(name))
		if n == "" {
			return
		}
		m[n] = fn
	}

	scan := bufio.NewScanner(bytes.NewReader(formulajsCatalogRaw))
	for scan.Scan() {
		line := strings.TrimSpace(scan.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		nm := strings.ToLower(line)
		if _, exists := m[nm]; exists {
			continue
		}
		put(nm, func(args []string) (string, error) {
			return formulajsEmit(nm, args)
		})
	}

	// Hand-tuned implementations (must win over generic formulajs emit).
	put("if", builtinIF)
	put("and", builtinAND)
	put("or", builtinOR)
	put("not", builtinNOT)
	put("sum", builtinSUM)
	put("average", builtinAVERAGE)
	put("min", builtinMIN)
	put("max", builtinMAX)
	put("count", builtinCOUNT)
	put("concat", builtinCONCAT)
	put("textjoin", builtinTEXTJOIN)

	return m
}