text/template: provide a way to trim leading and trailing space between actions
Borrowing a suggestion from the issue listed below, we modify the lexer to
trim spaces at the beginning (end) of a block of text if the action immediately
before (after) is marked with a minus sign. To avoid parsing/lexing ambiguity,
we require an ASCII space between the minus sign and the rest of the action.
Thus:
{{23 -}}
<
{{- 45}}
produces the output
23<45
All the work is done in the lexer. The modification is invisible to the parser
or any outside package (except I guess for noticing some gaps in the input
if one tracks error positions). Thus it slips in without worry in text/template
and html/template both.
Fixes long-requested issue #9969.
Change-Id: I3774be650bfa6370cb993d0899aa669c211de7b2
Reviewed-on: https://go-review.googlesource.com/14391
Reviewed-by: Andrew Gerrand <adg@golang.org>
diff --git a/src/text/template/exec_test.go b/src/text/template/exec_test.go
index 07ebb55..9fd0132 100644
--- a/src/text/template/exec_test.go
+++ b/src/text/template/exec_test.go
@@ -797,18 +797,19 @@
}
// Use different delimiters to test Set.Delims.
+// Also test the trimming of leading and trailing spaces.
const treeTemplate = `
- (define "tree")
+ (- define "tree" -)
[
- (.Val)
- (with .Left)
- (template "tree" .)
- (end)
- (with .Right)
- (template "tree" .)
- (end)
+ (- .Val -)
+ (- with .Left -)
+ (template "tree" . -)
+ (- end -)
+ (- with .Right -)
+ (- template "tree" . -)
+ (- end -)
]
- (end)
+ (- end -)
`
func TestTree(t *testing.T) {
@@ -853,19 +854,13 @@
t.Fatal("parse error:", err)
}
var b bytes.Buffer
- stripSpace := func(r rune) rune {
- if r == '\t' || r == '\n' {
- return -1
- }
- return r
- }
const expect = "[1[2[3[4]][5[6]]][7[8[9]][10[11]]]]"
// First by looking up the template.
err = tmpl.Lookup("tree").Execute(&b, tree)
if err != nil {
t.Fatal("exec error:", err)
}
- result := strings.Map(stripSpace, b.String())
+ result := b.String()
if result != expect {
t.Errorf("expected %q got %q", expect, result)
}
@@ -875,7 +870,7 @@
if err != nil {
t.Fatal("exec error:", err)
}
- result = strings.Map(stripSpace, b.String())
+ result = b.String()
if result != expect {
t.Errorf("expected %q got %q", expect, result)
}
