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

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

lexer/lexer.go

@@ -1,31 +1,17 @@
 // Package lexer provides basic helpers to implement parsers
 package lexer
 
-import (
-	"errors"
-	"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 {
-	for fn != nil {
-		var err error
+	var err error
 
+	for fn != nil && err == nil {
 		fn, err = fn()
-		switch {
-		case errors.Is(err, io.EOF):
-			// EOF
-			return nil
-		case err != nil:
-			// failed
-			return err
-		}
 	}
 
-	// ended
-	return nil
+	return err
 }

lexer/position.go

@@ -1,66 +0,0 @@
-package lexer
-
-import "fmt"
-
-// Position indicates a line and column pair on a file.
-// Counting starts at 1.
-type Position struct {
-	Line   int
-	Column int
-}
-
-// String generates a pretty "(Line, Column)"" representation of the Position
-func (p Position) String() string {
-	if p.Line == 0 {
-		p.Reset()
-	}
-
-	return fmt.Sprintf("(%v, %v)", p.Line, p.Column)
-}
-
-// GoString generates a string representation of the Position for %#v usage
-func (p Position) GoString() string {
-	if p.Line == 0 {
-		p.Reset()
-	}
-
-	return fmt.Sprintf("lexer.Position{%v, %v}", p.Line, p.Column)
-}
-
-// Reset places a position at (1,1)
-func (p *Position) Reset() {
-	p.Line, p.Column = 1, 1
-}
-
-// Step moves the column one place
-func (p *Position) Step() {
-	if p.Line == 0 {
-		p.Reset()
-	}
-
-	p.Column++
-}
-
-// StepN moves the column N places forward
-func (p *Position) StepN(n int) {
-	if p.Line == 0 {
-		p.Reset()
-	}
-
-	switch {
-	case n > 0:
-		p.Column += n
-	default:
-		panic(fmt.Errorf("invalid %v increment", n))
-	}
-}
-
-// StepLine moves position to the start of the next line
-func (p *Position) StepLine() {
-	if p.Line == 0 {
-		p.Reset()
-	}
-
-	p.Line++
-	p.Column = 1
-}