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

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

lexer/error.go

@@ -1,54 +0,0 @@
-package lexer
-
-import (
-	"errors"
-	"fmt"
-	"strings"
-)
-
-var (
-	_ error = (*Error)(nil)
-)
-
-var (
-	// ErrUnacceptableRune indicates the read rune isn't acceptable in the context
-	ErrUnacceptableRune = errors.New("rune not acceptable in context")
-
-	// ErrNotImplemented indicates something hasn't been implemented yet
-	ErrNotImplemented = errors.New("not implemented")
-)
-
-// Error represents a generic parsing error
-type Error struct {
-	Filename string
-	Line     int
-	Column   int
-
-	Content string
-	Err     error
-}
-
-func (err Error) Error() string {
-	var s []string
-
-	switch {
-	case err.Line > 0 || err.Column > 0:
-		s = append(s, fmt.Sprintf("%s:%v:%v", err.Filename, err.Line, err.Column))
-	case err.Filename != "":
-		s = append(s, err.Filename)
-	}
-
-	if err.Err != nil {
-		s = append(s, err.Err.Error())
-	}
-
-	if err.Content != "" {
-		s = append(s, fmt.Sprintf("%q", err.Content))
-	}
-
-	return strings.Join(s, ": ")
-}
-
-func (err Error) Unwrap() error {
-	return err.Err
-}

lexer/lexer.go

@@ -1,31 +0,0 @@
-// 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
-
-		fn, err = fn()
-		switch {
-		case errors.Is(err, io.EOF):
-			// EOF
-			return nil
-		case err != nil:
-			// failed
-			return err
-		}
-	}
-
-	// ended
-	return nil
-}

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
-}

lexer/runes.go

@@ -1,41 +0,0 @@
-package lexer
-
-import (
-	"strings"
-	"unicode"
-)
-
-// NewIsNot generates a rune condition checker that reverses the
-// decision of the given checker.
-func NewIsNot(cond func(rune) bool) func(rune) bool {
-	return func(r rune) bool {
-		return !cond(r)
-	}
-}
-
-// NewIsIn generates a rune condition checker that accepts runes
-// contained on the provided string
-func NewIsIn(s string) func(rune) bool {
-	return func(r rune) bool {
-		return strings.ContainsRune(s, r)
-	}
-}
-
-// NewIsOneOf generates a run condition checker that accepts runes
-// accepted by any of the given checkers
-func NewIsOneOf(s ...func(rune) bool) func(rune) bool {
-	return func(r rune) bool {
-		for _, cond := range s {
-			if cond(r) {
-				return true
-			}
-		}
-		return false
-	}
-}
-
-// IsSpace reports whether the rune is a space character as
-// defined by Unicode's White Space property
-func IsSpace(r rune) bool {
-	return unicode.IsSpace(r)
-}

runes/docs.go

@@ -0,0 +1,2 @@
+// Package runes helps us work with runes
+package runes

runes/reader.go

@@ -1,8 +1,7 @@
-package lexer
+package runes
 
 import (
 	"bytes"
-	"errors"
 	"io"
 	"strings"
 	"unicode/utf8"
@@ -19,14 +18,7 @@ const (
 
 // implemented interfaces
 var (
-	_ io.RuneReader  = (*Reader)(nil)
+	_ io.RuneReader = (*Reader)(nil)
-	_ io.RuneScanner = (*Reader)(nil)
-)
-
-var (
-	// ErrInvalidUnreadRune indicates UnreadRune() was calls after an
-	// action other than a successful ReadRune()
-	ErrInvalidUnreadRune = errors.New("invalid UnreadRune() call")
 )
 
 // Reader is a RuneReader aimed at implementing text parsers
@@ -36,8 +28,6 @@ type Reader struct {
 	buf    []byte
 	off    int
 	cursor int
-
-	lastRuneSize int
 }
 
 // String returns what's already Read but not yet emitted or discarded
@@ -64,9 +54,6 @@ func (b *Reader) Discard() {
 		// step
 		b.off = b.cursor
 	}
-
-	// and prevent UnreadRune()
-	b.lastRuneSize = -1
 }
 
 // ready tells how many bytes are ready to decode
@@ -152,8 +139,6 @@ func (b *Reader) ReadRune() (rune, int, error) {
 	for {
 		err := b.needsBytes(count)
 		if err != nil {
-			b.lastRuneSize = -1
-
 			return 0, 0, err
 		}
 
@@ -168,71 +153,9 @@ func (b *Reader) ReadRune() (rune, int, error) {
 
 	// decode rune
 	r, l := utf8.DecodeRune(b.buf[b.cursor:])
-	// step over
-	b.cursor += l
-	// and remember for UnreadRune()
-	b.lastRuneSize = l
-
 	return r, l, nil
 }
 
-// UnreadRune moves the cursor where it was before the last call to ReadRune
-func (b *Reader) UnreadRune() error {
-	if b.lastRuneSize > 0 {
-		b.cursor -= b.lastRuneSize
-		b.lastRuneSize = -1
-		return nil
-	}
-
-	return ErrInvalidUnreadRune
-}
-
-// PeekRune returns information about the next rune without moving the
-// cursor
-func (b *Reader) PeekRune() (rune, int, error) {
-	r, l, err := b.ReadRune()
-	if err != nil {
-		return r, l, err
-	}
-	err = b.UnreadRune()
-	return r, l, 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 (b *Reader) Accept(cond func(r rune) bool) bool {
-	r, _, err := b.ReadRune()
-	switch {
-	case err != nil:
-		return false
-	case cond(r):
-		return true
-	default:
-		_ = b.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 (b *Reader) AcceptAll(cond func(r rune) bool) bool {
-	var accepted bool
-
-	for {
-		r, _, err := b.ReadRune()
-		switch {
-		case err != nil:
-			return accepted
-		case cond(r):
-			accepted = true
-		default:
-			_ = b.UnreadRune()
-			return accepted
-		}
-	}
-}
-
 // NewReader creates a new runes [Reader] using the given [io.Reader]
 func NewReader(r io.Reader) *Reader {
 	if r == nil {