build-sys: import build system from darvaza.org/core

Signed-off-by: Alejandro Mery <amery@jpi.io>

lexer/lexer.go

@@ -1,54 +0,0 @@
-// Package lexer provides basic helpers to implement parsers
-package lexer
-
-import "io"
-
-// StateFn is a State Function of the parser
-type StateFn func() (StateFn, error)
-
-// Run runs a state machine until the state function either
-// returns nil or an error
-func Run(fn StateFn) error {
-	var err error
-
-	for fn != nil && err == nil {
-		fn, err = fn()
-	}
-
-	return err
-}
-
-// Accept consumes a rune from the source if it meets the condition.
-// it returns true if the condition was met and false if it wasn't.
-func Accept(src io.RuneScanner, cond func(r rune) bool) bool {
-	r, _, err := src.ReadRune()
-	switch {
-	case err != nil:
-		return false
-	case cond(r):
-		return true
-	default:
-		_ = src.UnreadRune()
-		return false
-	}
-}
-
-// AcceptAll consumes runes from the source as long as they meet the
-// condition. it returns true if the condition was met for at least one rune,
-// and false if it wasn't.
-func AcceptAll(src io.RuneScanner, cond func(r rune) bool) bool {
-	var accepted bool
-
-	for {
-		r, _, err := src.ReadRune()
-		switch {
-		case err != nil:
-			return accepted
-		case cond(r):
-			accepted = true
-		default:
-			_ = src.UnreadRune()
-			return accepted
-		}
-	}
-}