[go] go/scanner: allow backtick in raw string literal
Gobot Gobot (Gerrit)
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Giovanni Bajo (Gerrit)
1 comment:
Missing space here
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Yasuhiro MATSUMOTO (Gerrit)
1 comment:
File src/go/scanner/scanner.go:
Patch Set #1, Line 511:
return c[:j]Odd number of backquote shoud be an error. So last one is invalid.
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Jan Mercl (Gerrit)
Patch set 1:Code-Review -1
Ryuichi Hayashida (Gerrit)
Ryuichi Hayashida has uploaded this change for review.
go/scanner: allow backtick in raw string literal
This commit enables to embed ` in raw string literal. Doubled backtick
`` now means one ` in raw string literal as following.
// Outputs 'foo `bar'
fmt.Println(`foo `` bar`)
// Outputs '`'
fmt.Println(````)
// Outputs '``'
fmt.Println(``````)
GitHub issue for proposal of this feature:
https://github.com/golang/go/issues/23228
Fixes #23228
Change-Id: I5708cb3538fb49ca8669ad56e22b15a36461925a
---
M doc/go_spec.html
M src/go/scanner/scanner.go
M src/go/scanner/scanner_test.go
M test/string_lit.go
4 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/doc/go_spec.html b/doc/go_spec.html
index ebf1cef..fe36113 100644
--- a/doc/go_spec.html
+++ b/doc/go_spec.html
@@ -456,7 +456,12 @@
contain newlines.
Carriage return characters ('\r') inside raw string literals
are discarded from the raw string value.
+To contain back quotes in raw string literals, doubled back quotes '``'
+are available. They means one back quotes in raw string literals.
</p>
+<pre>
+`foo `` bar` // Equivalent to "foo ` bar"
+</pre>
<p>
Interpreted string literals are character sequences between double
quotes, as in <code>"bar"</code>.
diff --git a/src/go/scanner/scanner.go b/src/go/scanner/scanner.go
index a86e4eb..0257b2d 100644
--- a/src/go/scanner/scanner.go
+++ b/src/go/scanner/scanner.go
@@ -492,11 +492,31 @@
return c[:i]
}
+func stripDoubledBackquotes(b []byte) []byte {
+ l := len(b)
+ c := make([]byte, l)
+ i, j := 0, 0
+ for {
+ c[j] = b[i]
+ j++
+ if i == l-1 {
+ break
+ }
+ if b[i] == '`' && b[i+1] == '`' {
+ i += 2
+ } else {
+ i++
+ }
+ }
+ return c[:j]
+}
+
func (s *Scanner) scanRawString() string {
// '`' opening already consumed
offs := s.offset - 1
hasCR := false
+ hasBQ := false
for {
ch := s.ch
if ch < 0 {
@@ -505,7 +525,12 @@
}
s.next()
if ch == '`' {
- break
+ if s.ch == '`' {
+ s.next()
+ hasBQ = true
+ } else {
+ break
+ }
}
if ch == '\r' {
hasCR = true
@@ -516,6 +541,9 @@
if hasCR {
lit = stripCR(lit)
}
+ if hasBQ {
+ lit = stripDoubledBackquotes(lit)
+ }
return string(lit)
}
diff --git a/src/go/scanner/scanner_test.go b/src/go/scanner/scanner_test.go
index ff41c03..564254d 100644
--- a/src/go/scanner/scanner_test.go
+++ b/src/go/scanner/scanner_test.go
@@ -90,6 +90,9 @@
},
{token.STRING, "`\r`", literal},
{token.STRING, "`foo\r\nbar`", literal},
+ {token.STRING, "`foo``bar`", literal},
+ {token.STRING, "````", literal},
+ {token.STRING, "`foo````bar`", literal},
// Operators and delimiters
{token.ADD, "+", operator},
@@ -285,6 +288,7 @@
elit = e.lit
if elit[0] == '`' {
elit = string(stripCR([]byte(elit)))
+ elit = string(stripDoubledBackquotes([]byte(elit)))
}
} else if e.tok.IsKeyword() {
elit = e.lit
diff --git a/test/string_lit.go b/test/string_lit.go
index 4751b82..f92ddad 100644
--- a/test/string_lit.go
+++ b/test/string_lit.go
@@ -93,6 +93,8 @@
`\000\123\x00\312\xFE\u0123\ubabe\U0000babe`,
"backslashes 2 (backquote)")
assert("\\x\\u\\U\\", `\x\u\U\`, "backslash 3 (backquote)")
+ assert(`foo `` bar`, "foo ` bar", "backquote in raw string literal")
+ assert(````, "`", "backquote-only raw string literal")
// test large and surrogate-half runes. perhaps not the most logical place for these tests.
var r int32
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Brad Fitzpatrick (Gerrit)
-2 to prevent accidental merge, pending proposal issue's approval.
Patch set 1:Code-Review -2
Andrew Bonventre (Gerrit)
Andrew Bonventre abandoned this change.
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