Remove support for using \ for line continuation.

pkg/eval/builtin_special_test.go

@@ -163,15 +163,15 @@ func TestUse(t *testing.T) {
 }
 
 // Regression test for #1072
-func TestUse_WarnsAboutDeprecatedSyntax(t *testing.T) {
+func TestUse_WarnsAboutDeprecatedFeatures(t *testing.T) {
 	restore := prog.SetShowDeprecations(true)
 	defer restore()
 	libdir, cleanup := util.InTestDir()
 	defer cleanup()
-	mustWriteFile("dep.elv", []byte("a = \\\n1"), 0600)
+	mustWriteFile("dep.elv", []byte("x = (ord 1)"), 0600)
 
 	TestWithSetup(t, func(ev *Evaler) { ev.SetLibDir(libdir) },
-		// Importing module triggers check for deprecated syntax features
+		// Importing module triggers check for deprecated features
 		That("use dep").PrintsStderrWith("is deprecated"),
 	)
 }

pkg/parse/parse.go

@@ -18,7 +18,6 @@ import (
 	"unicode"
 
 	"github.com/elves/elvish/pkg/diag"
-	"github.com/elves/elvish/pkg/prog"
 )
 
 // Tree represents a parsed tree.
@@ -958,8 +957,7 @@ spaces:
 				}
 				ps.next()
 			}
-		case r == '\\' || r == '^':
-			p := ps.pos
+		case r == '^':
 			// Line continuation is like inline whitespace.
 			ps.next()
 			switch ps.peek() {
@@ -968,14 +966,8 @@ spaces:
 				if ps.peek() == '\n' {
 					ps.next()
 				}
-				if r == '\\' {
-					backslashLineCont(ps, p)
-				}
 			case '\n':
 				ps.next()
-				if r == '\\' {
-					backslashLineCont(ps, p)
-				}
 			case eof:
 				ps.error(errShouldBeNewline)
 			default:
@@ -989,20 +981,6 @@ spaces:
 	addSep(n, ps)
 }
 
-func backslashLineCont(ps *parser, p int) {
-	if !prog.ShowDeprecations || ps.warn == nil {
-		return
-	}
-	err := diag.Error{
-		Type:    "deprecation",
-		Message: "using \\ for line continuation is deprecated; use ^ instead",
-		Context: diag.Context{
-			Name: ps.srcName, Source: ps.src,
-			Ranging: diag.Ranging{From: p, To: p + 1}},
-	}
-	fmt.Fprintln(ps.warn, err.Show(""))
-}
-
 // IsInlineWhitespace reports whether r is an inline whitespace character.
 // Currently this includes space (Unicode 0x20) and tab (Unicode 0x9).
 func IsInlineWhitespace(r rune) bool {

pkg/parse/parse_test.go

@@ -1,14 +1,9 @@
 package parse
 
 import (
-	"bytes"
 	"fmt"
-	"io"
-	"io/ioutil"
 	"os"
 	"testing"
-
-	"github.com/elves/elvish/pkg/prog"
 )
 
 func a(c ...interface{}) ast {
@@ -255,9 +250,6 @@ var goodCases = []struct {
 	// Line continuation: "^\n" is considered whitespace
 	{"a b^\nc", ast{
 		"Chunk/Pipeline/Form", fs{"Head": "a", "Args": []string{"b", "c"}}}},
-	// Same test using deprecated "\\\n".
-	{"a b\\\nc", ast{
-		"Chunk/Pipeline/Form", fs{"Head": "a", "Args": []string{"b", "c"}}}},
 
 	// Carriage returns are normally treated the same as newlines:
 	// Separating pipelines in a chunk
@@ -275,10 +267,10 @@ var goodCases = []struct {
 			"Elements": []string{"a", "b"}}})},
 
 	// However, in line continuations, \r\n is treated as a single newline
-	{"a b\\\r\nc", ast{
+	{"a b^\r\nc", ast{
 		"Chunk/Pipeline/Form", fs{"Head": "a", "Args": []string{"b", "c"}}}},
 	// But a lone \r also works
-	{"a b\\\rc", ast{
+	{"a b^\rc", ast{
 		"Chunk/Pipeline/Form", fs{"Head": "a", "Args": []string{"b", "c"}}}},
 
 	// Comments in chunks.
@@ -321,27 +313,6 @@ func TestParse(t *testing.T) {
 	}
 }
 
-func TestParseDeprecations(t *testing.T) {
-	restore := prog.SetShowDeprecations(true)
-	defer restore()
-
-	r, w := io.Pipe()
-	msgChan := make(chan []byte)
-	go func() {
-		msg, _ := ioutil.ReadAll(r)
-		msgChan <- msg
-		r.Close()
-	}()
-	ParseWithDeprecation(Source{Name: "[test]", Code: "a\\\nb"}, w)
-	w.Close()
-
-	msg := <-msgChan
-	wantMsg := []byte("using \\ for line continuation is deprecated")
-	if !bytes.Contains(msg, wantMsg) {
-		t.Errorf("got message %q, want message to contain %q", msg, wantMsg)
-	}
-}
-
 var parseErrorTests = []struct {
 	src      string
 	errPart  string
@@ -391,7 +362,7 @@ var parseErrorTests = []struct {
 	// Unmatched {.
 	{src: "{ a", errAtEnd: true, errMsg: "should be '}'"},
 	// Unfinished line continuation.
-	{src: `a \`, errAtEnd: true, errMsg: "should be newline"},
+	{src: `a ^`, errAtEnd: true, errMsg: "should be newline"},
 	// Backslash is otherwise not allowed.
 	{src: `a \a`, errPart: `\`, errMsg: `unexpected rune '\\'`},
 }