parser: TextParser [WIP]

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

parser/parser.go

@@ -0,0 +1,2 @@
+// Package parser implements some common logic of asciigoat based parsers
+package parser

parser/text.go

@@ -0,0 +1,72 @@
+package parser
+
+import (
+	"bytes"
+	"io"
+	"strings"
+
+	"asciigoat.org/core/lexer"
+)
+
+// TextParser ...
+type TextParser struct {
+	src *lexer.Reader
+	pos lexer.Position
+}
+
+// Position ...
+func (p *TextParser) Position() lexer.Position {
+	return p.pos
+}
+
+// StepLine ...
+func (p *TextParser) StepLine() {
+	p.src.Discard()
+	p.pos.StepLine()
+}
+
+// Step ...
+func (p *TextParser) Step() {
+	s := p.src.Emit()
+	p.pos.StepN(len(s))
+}
+
+// Emit ...
+func (p *TextParser) Emit() Token {
+	t := Token{
+		Value:    p.src.Emit(),
+		Position: p.pos,
+	}
+
+	p.pos.StepN(t.Len())
+	return t
+}
+
+// Peek ...
+func (p *TextParser) Peek() string {
+	return p.src.String()
+}
+
+// NewTextParser ...
+func NewTextParser(r io.Reader) *TextParser {
+	if r == nil {
+		r = strings.NewReader("")
+	}
+
+	p := &TextParser{
+		src: lexer.NewReader(r),
+	}
+	p.pos.Reset()
+
+	return p
+}
+
+// NewTextParserBytes ...
+func NewTextParserBytes(b []byte) *TextParser {
+	return NewTextParser(bytes.NewReader(b))
+}
+
+// NewTextParserString ...
+func NewTextParserString(s string) *TextParser {
+	return NewTextParser(strings.NewReader(s))
+}

parser/token.go

@@ -0,0 +1,31 @@
+package parser
+
+import (
+	"fmt"
+
+	"asciigoat.org/core/lexer"
+)
+
+// Token ...
+type Token struct {
+	lexer.Position
+
+	Type  uint
+	Value string
+}
+
+// Len ...
+func (t Token) Len() int {
+	return len(t.Value)
+}
+
+// String generates the '%v' value
+func (t Token) String() string {
+	return t.Value
+}
+
+// GoString generates the '%#v' value
+func (t Token) GoString() string {
+	return fmt.Sprintf("Token{Position{%v,%v}, %v, %q}",
+		t.Line, t.Column, t.Type, t.Value)
+}