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path: root/src/text/template/parse/lex.go
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-rw-r--r--src/text/template/parse/lex.go84
1 files changed, 42 insertions, 42 deletions
diff --git a/src/text/template/parse/lex.go b/src/text/template/parse/lex.go
index e41373a002..6784071b11 100644
--- a/src/text/template/parse/lex.go
+++ b/src/text/template/parse/lex.go
@@ -92,15 +92,14 @@ const eof = -1
// If the action begins "{{- " rather than "{{", then all space/tab/newlines
// preceding the action are trimmed; conversely if it ends " -}}" the
// leading spaces are trimmed. This is done entirely in the lexer; the
-// parser never sees it happen. We require an ASCII space to be
-// present to avoid ambiguity with things like "{{-3}}". It reads
+// parser never sees it happen. We require an ASCII space (' ', \t, \r, \n)
+// to be present to avoid ambiguity with things like "{{-3}}". It reads
// better with the space present anyway. For simplicity, only ASCII
-// space does the job.
+// does the job.
const (
- spaceChars = " \t\r\n" // These are the space characters defined by Go itself.
- leftTrimMarker = "- " // Attached to left delimiter, trims trailing spaces from preceding text.
- rightTrimMarker = " -" // Attached to right delimiter, trims leading spaces from following text.
- trimMarkerLen = Pos(len(leftTrimMarker))
+ spaceChars = " \t\r\n" // These are the space characters defined by Go itself.
+ trimMarker = '-' // Attached to left/right delimiter, trims trailing spaces from preceding/following text.
+ trimMarkerLen = Pos(1 + 1) // marker plus space before or after
)
// stateFn represents the state of the scanner as a function that returns the next state.
@@ -108,19 +107,18 @@ type stateFn func(*lexer) stateFn
// lexer holds the state of the scanner.
type lexer struct {
- name string // the name of the input; used only for error reports
- input string // the string being scanned
- leftDelim string // start of action
- rightDelim string // end of action
- trimRightDelim string // end of action with trim marker
- emitComment bool // emit itemComment tokens.
- pos Pos // current position in the input
- start Pos // start position of this item
- width Pos // width of last rune read from input
- items chan item // channel of scanned items
- parenDepth int // nesting depth of ( ) exprs
- line int // 1+number of newlines seen
- startLine int // start line of this item
+ name string // the name of the input; used only for error reports
+ input string // the string being scanned
+ leftDelim string // start of action
+ rightDelim string // end of action
+ emitComment bool // emit itemComment tokens.
+ pos Pos // current position in the input
+ start Pos // start position of this item
+ width Pos // width of last rune read from input
+ items chan item // channel of scanned items
+ parenDepth int // nesting depth of ( ) exprs
+ line int // 1+number of newlines seen
+ startLine int // start line of this item
}
// next returns the next rune in the input.
@@ -213,15 +211,14 @@ func lex(name, input, left, right string, emitComment bool) *lexer {
right = rightDelim
}
l := &lexer{
- name: name,
- input: input,
- leftDelim: left,
- rightDelim: right,
- trimRightDelim: rightTrimMarker + right,
- emitComment: emitComment,
- items: make(chan item),
- line: 1,
- startLine: 1,
+ name: name,
+ input: input,
+ leftDelim: left,
+ rightDelim: right,
+ emitComment: emitComment,
+ items: make(chan item),
+ line: 1,
+ startLine: 1,
}
go l.run()
return l
@@ -251,7 +248,7 @@ func lexText(l *lexer) stateFn {
ldn := Pos(len(l.leftDelim))
l.pos += Pos(x)
trimLength := Pos(0)
- if strings.HasPrefix(l.input[l.pos+ldn:], leftTrimMarker) {
+ if hasLeftTrimMarker(l.input[l.pos+ldn:]) {
trimLength = rightTrimLength(l.input[l.start:l.pos])
}
l.pos -= trimLength
@@ -280,7 +277,7 @@ func rightTrimLength(s string) Pos {
// atRightDelim reports whether the lexer is at a right delimiter, possibly preceded by a trim marker.
func (l *lexer) atRightDelim() (delim, trimSpaces bool) {
- if strings.HasPrefix(l.input[l.pos:], l.trimRightDelim) { // With trim marker.
+ if hasRightTrimMarker(l.input[l.pos:]) && strings.HasPrefix(l.input[l.pos+trimMarkerLen:], l.rightDelim) { // With trim marker.
return true, true
}
if strings.HasPrefix(l.input[l.pos:], l.rightDelim) { // Without trim marker.
@@ -297,7 +294,7 @@ func leftTrimLength(s string) Pos {
// lexLeftDelim scans the left delimiter, which is known to be present, possibly with a trim marker.
func lexLeftDelim(l *lexer) stateFn {
l.pos += Pos(len(l.leftDelim))
- trimSpace := strings.HasPrefix(l.input[l.pos:], leftTrimMarker)
+ trimSpace := hasLeftTrimMarker(l.input[l.pos:])
afterMarker := Pos(0)
if trimSpace {
afterMarker = trimMarkerLen
@@ -342,7 +339,7 @@ func lexComment(l *lexer) stateFn {
// lexRightDelim scans the right delimiter, which is known to be present, possibly with a trim marker.
func lexRightDelim(l *lexer) stateFn {
- trimSpace := strings.HasPrefix(l.input[l.pos:], rightTrimMarker)
+ trimSpace := hasRightTrimMarker(l.input[l.pos:])
if trimSpace {
l.pos += trimMarkerLen
l.ignore()
@@ -369,7 +366,7 @@ func lexInsideAction(l *lexer) stateFn {
return l.errorf("unclosed left paren")
}
switch r := l.next(); {
- case r == eof || isEndOfLine(r):
+ case r == eof:
return l.errorf("unclosed action")
case isSpace(r):
l.backup() // Put space back in case we have " -}}".
@@ -439,7 +436,7 @@ func lexSpace(l *lexer) stateFn {
}
// Be careful about a trim-marked closing delimiter, which has a minus
// after a space. We know there is a space, so check for the '-' that might follow.
- if strings.HasPrefix(l.input[l.pos-1:], l.trimRightDelim) {
+ if hasRightTrimMarker(l.input[l.pos-1:]) && strings.HasPrefix(l.input[l.pos-1+trimMarkerLen:], l.rightDelim) {
l.backup() // Before the space.
if numSpaces == 1 {
return lexRightDelim // On the delim, so go right to that.
@@ -526,7 +523,7 @@ func lexFieldOrVariable(l *lexer, typ itemType) stateFn {
// day to implement arithmetic.
func (l *lexer) atTerminator() bool {
r := l.peek()
- if isSpace(r) || isEndOfLine(r) {
+ if isSpace(r) {
return true
}
switch r {
@@ -657,15 +654,18 @@ Loop:
// isSpace reports whether r is a space character.
func isSpace(r rune) bool {
- return r == ' ' || r == '\t'
-}
-
-// isEndOfLine reports whether r is an end-of-line character.
-func isEndOfLine(r rune) bool {
- return r == '\r' || r == '\n'
+ return r == ' ' || r == '\t' || r == '\r' || r == '\n'
}
// isAlphaNumeric reports whether r is an alphabetic, digit, or underscore.
func isAlphaNumeric(r rune) bool {
return r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r)
}
+
+func hasLeftTrimMarker(s string) bool {
+ return len(s) >= 2 && s[0] == trimMarker && isSpace(rune(s[1]))
+}
+
+func hasRightTrimMarker(s string) bool {
+ return len(s) >= 2 && isSpace(rune(s[0])) && s[1] == trimMarker
+}
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