Mercurial > hg-stable
changeset 25783:1f6878c87c25
templater: introduce one-pass parsing of nested template strings
Instead of re-parsing quoted strings as templates, the tokenizer can delegate
the parsing of nested template strings to the parser. It has two benefits:
1. syntax errors can be reported with absolute positions
2. nested template can use quotes just like shell: "{"{rev}"}"
It doesn't sound nice that the tokenizer recurses into the parser. We could
instead make the tokenize itself recursive, but it would be much more
complicated because we would have to adjust binding strengths carefully and
put dummy infix operators to concatenate template fragments.
Now "string" token without r"" never appears. It will be removed by the next
patch.
| author | Yuya Nishihara <yuya@tcha.org> |
|---|---|
| date | Mon, 15 Jun 2015 23:11:35 +0900 |
| parents | babd2c93bd99 |
| children | 33e613687dab |
| files | mercurial/templater.py tests/test-command-template.t tests/test-doctest.py |
| diffstat | 3 files changed, 54 insertions(+), 7 deletions(-) [+] |
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--- a/mercurial/templater.py Mon Jun 15 23:03:30 2015 +0900 +++ b/mercurial/templater.py Mon Jun 15 23:11:35 2015 +0900 @@ -24,6 +24,7 @@ "symbol": (0, ("symbol",), None), "string": (0, ("template",), None), "rawstring": (0, ("rawstring",), None), + "template": (0, ("template",), None), "end": (0, None, None), } @@ -35,6 +36,11 @@ pass elif c in "(,)%|": # handle simple operators yield (c, None, pos) + elif c in '"\'': # handle quoted templates + s = pos + 1 + data, pos = _parsetemplate(program, s, end, c) + yield ('template', data, s) + pos -= 1 elif (c in '"\'' or c == 'r' and program[pos:pos + 2] in ("r'", 'r"')): # handle quoted strings if c == 'r': @@ -89,7 +95,7 @@ pos += 1 token = 'rawstring' else: - token = 'string' + token = 'template' quote = program[pos:pos + 2] s = pos = pos + 2 while pos < end: # find closing escaped quote @@ -102,6 +108,8 @@ data = program[s:pos].decode('string-escape') except ValueError: # unbalanced escapes raise error.ParseError(_("syntax error"), s) + if token == 'template': + data = _parsetemplate(data, 0, len(data))[0] yield (token, data, s) pos += 1 break @@ -127,27 +135,47 @@ pos += 1 raise error.ParseError(_("unterminated template expansion"), start) -def _parsetemplate(tmpl, start, stop): +def _parsetemplate(tmpl, start, stop, quote=''): + r""" + >>> _parsetemplate('foo{bar}"baz', 0, 12) + ([('string', 'foo'), ('symbol', 'bar'), ('string', '"baz')], 12) + >>> _parsetemplate('foo{bar}"baz', 0, 12, quote='"') + ([('string', 'foo'), ('symbol', 'bar')], 9) + >>> _parsetemplate('foo"{bar}', 0, 9, quote='"') + ([('string', 'foo')], 4) + >>> _parsetemplate(r'foo\"bar"baz', 0, 12, quote='"') + ([('string', 'foo"'), ('string', 'bar')], 9) + >>> _parsetemplate(r'foo\\"bar', 0, 10, quote='"') + ([('string', 'foo\\\\')], 6) + """ parsed = [] + sepchars = '{' + quote pos = start p = parser.parser(elements) while pos < stop: - n = tmpl.find('{', pos, stop) + n = min((tmpl.find(c, pos, stop) for c in sepchars), + key=lambda n: (n < 0, n)) if n < 0: parsed.append(('string', tmpl[pos:stop])) pos = stop break + c = tmpl[n] bs = (n - pos) - len(tmpl[pos:n].rstrip('\\')) if bs % 2 == 1: # escaped (e.g. '\{', '\\\{', but not '\\{') - parsed.append(('string', (tmpl[pos:n - 1] + "{"))) + parsed.append(('string', (tmpl[pos:n - 1] + c))) pos = n + 1 continue if n > pos: parsed.append(('string', tmpl[pos:n])) + if c == quote: + return parsed, n + 1 parseres, pos = p.parse(tokenize(tmpl, n + 1, stop)) parsed.append(parseres) + + if quote: + raise error.ParseError(_("unterminated string"), start) return parsed, pos def compiletemplate(tmpl, context): @@ -182,7 +210,7 @@ def gettemplate(exp, context): if exp[0] == 'template': - return compiletemplate(exp[1], context) + return [compileexp(e, context, methods) for e in exp[1]] if exp[0] == 'symbol': # unlike runsymbol(), here 'symbol' is always taken as template name # even if it exists in mapping. this allows us to override mapping @@ -215,7 +243,7 @@ return v def buildtemplate(exp, context): - ctmpl = compiletemplate(exp[1], context) + ctmpl = [compileexp(e, context, methods) for e in exp[1]] if len(ctmpl) == 1: return ctmpl[0] # fast path for string with no template fragment return (runtemplate, ctmpl)
--- a/tests/test-command-template.t Mon Jun 15 23:03:30 2015 +0900 +++ b/tests/test-command-template.t Mon Jun 15 23:11:35 2015 +0900 @@ -2541,6 +2541,16 @@ abort: template filter 'datefilter' is not compatible with keyword 'author' [255] +Error in nested template: + + $ hg log -T '{"date' + hg: parse error at 2: unterminated string + [255] + + $ hg log -T '{"foo{date|=}"}' + hg: parse error at 11: syntax error + [255] + Thrown an error if a template function doesn't exist $ hg tip --template '{foo()}\n' @@ -2952,7 +2962,7 @@ $ hg log -r 2 -T "{if(rev, '{if(rev, r\'foo\')}')}"'\n' foo $ hg log -r 2 -T '{if(rev, "{if(rev, \")}")}\n' - hg: parse error at 11: unterminated string + hg: parse error at 21: unterminated string [255] $ hg log -r 2 -T '{if(rev, \"\\"")}\n' hg: parse error at 11: syntax error @@ -3069,6 +3079,14 @@ 3:\x6eo user, \x6eo domai\x6e 4:\x5c\x786eew bra\x5c\x786ech +Test quotes in nested expression are evaluated just like a $(command) +substitution in POSIX shells: + + $ hg log -R a -r 8 -T '{"{"{rev}:{node|short}"}"}\n' + 8:95c24699272e + $ hg log -R a -r 8 -T '{"{"\{{rev}} \"{node|short}\""}"}\n' + {8} "95c24699272e" + Test recursive evaluation: $ hg init r
--- a/tests/test-doctest.py Mon Jun 15 23:03:30 2015 +0900 +++ b/tests/test-doctest.py Mon Jun 15 23:11:35 2015 +0900 @@ -26,6 +26,7 @@ testmod('mercurial.store') testmod('mercurial.subrepo') testmod('mercurial.templatefilters') +testmod('mercurial.templater') testmod('mercurial.ui') testmod('mercurial.url') testmod('mercurial.util')