Lexer first commit

Author: antonmedv

ast/location.go

@@ -1,7 +1,7 @@
 package ast
 
 import (
-	"github.com/antonmedv/expr/internal/file"
+	"github.com/antonmedv/expr/file"
 )
 
 func (n *NilNode) SetLocation(l file.Location) {

ast/node.go

@@ -1,10 +1,9 @@
 package ast
 
 import (
+	"github.com/antonmedv/expr/file"
 	"reflect"
 	"regexp"
-
-	"github.com/antonmedv/expr/internal/file"
 )
 
 // Node represents items of abstract syntax tree.

checker/checker.go

@@ -5,8 +5,8 @@ import (
 	"reflect"
 
 	"github.com/antonmedv/expr/ast"
+	"github.com/antonmedv/expr/file"
 	"github.com/antonmedv/expr/internal/conf"
-	"github.com/antonmedv/expr/internal/file"
 	"github.com/antonmedv/expr/parser"
 )
 

compiler/compiler.go

@@ -3,12 +3,12 @@ package compiler
 import (
 	"encoding/binary"
 	"fmt"
+	"github.com/antonmedv/expr/file"
 	"math"
 	"reflect"
 
 	"github.com/antonmedv/expr/ast"
 	"github.com/antonmedv/expr/internal/conf"
-	"github.com/antonmedv/expr/internal/file"
 	"github.com/antonmedv/expr/parser"
 	. "github.com/antonmedv/expr/vm"
 )

internal/file/error.go renamed to file/error.go

@@ -8,10 +8,9 @@ import (
 	"golang.org/x/text/width"
 )
 
-// Error type which references a location within source and a message.
 type Error struct {
-	Location Location
-	Message  string
+	Location
+	Message string
 }
 
 const (
@@ -24,9 +23,13 @@ var (
 	wideInd = width.Widen.String(ind)
 )
 
-func (e *Error) Format(source *Source) string {
+func (e *Error) Error() string {
+	return e.Message
+}
+
+func (e *Error) Format(source *Source) error {
 	if e.Location.Empty() {
-		return e.Message
+		return fmt.Errorf(e.Message)
 	}
 	var result = fmt.Sprintf(
 		"%s (%d:%d)",
@@ -55,5 +58,5 @@ func (e *Error) Format(source *Source) string {
 		}
 		result += srcLine + indLine
 	}
-	return result
+	return fmt.Errorf(result)
 }

internal/file/location.go renamed to file/location.go

@@ -68,7 +68,7 @@ func (s *Source) updateOffsets() {
 func (s *Source) findLineOffset(line int) (int32, bool) {
 	if line == 1 {
 		return 0, true
-	} else if line > 1 && line <= int(len(s.lineOffsets)) {
+	} else if line > 1 && line <= len(s.lineOffsets) {
 		offset := s.lineOffsets[line-2]
 		return offset, true
 	}

internal/file/source.go renamed to file/source.go

@@ -5,14 +5,12 @@ import (
 )
 
 const (
-	unexpectedValue   = "%s got snippet '%v', want '%v'"
 	unexpectedSnippet = "%s got snippet '%s', want '%v'"
 	snippetNotFound   = "%s snippet not found, wanted '%v'"
 	snippetFound      = "%s snippet found at Line %d, wanted none"
 )
 
-// TestStringSource_SnippetMultiline snippets of text from a multiline source.
-func TestStringSource_SnippetMultiline(t *testing.T) {
+func TestStringSource_SnippetMultiLine(t *testing.T) {
 	source := NewSource("hello\nworld\nmy\nbub\n")
 	if str, found := source.Snippet(1); !found {
 		t.Errorf(snippetNotFound, t.Name(), 1)
@@ -41,8 +39,7 @@ func TestStringSource_SnippetMultiline(t *testing.T) {
 	}
 }
 
-// TestStringSource_SnippetSingleline snippets from a single line source.
-func TestStringSource_SnippetSingleline(t *testing.T) {
+func TestStringSource_SnippetSingleLine(t *testing.T) {
 	source := NewSource("hello, world")
 	if str, found := source.Snippet(1); !found {
 		t.Errorf(snippetNotFound, t.Name(), 1)