racket at-exp include curly bracket - racket

How can I use at-exp to include blew raw string:
package foo
}
import (
I write like this, but it cannot include the "}" character:
#lang at-exp racket/base
(define code #S{
package foo
}
import (
}
How to include special character like "{}" in the raw part.

Use #S|{...}| for that: since the closing part is }|, plain }s would not be special. Also, remember to use |# instead of just # for nested forms. And if you need another different quotation since you want to use }|s too, you can add more things between, as in #S|==={...}===|. See the documentation page for details (look for |{s, and see section 2.4.1).
As for what you've found: this is not the same. What you're doing there is a nested "{" string, which you can use for each unbalanced character. But that is much less convenient than the above alternative quotation syntax.

oh, sorry, I find use #|"{"| is ok.

Related

Noweb does not cross-reference Perl identifiers delimited on the left by #

Consider this Noweb source file named quux.nw:
\documentclass{article}
\usepackage{noweb}
\usepackage[colorlinks]{hyperref}
\begin{document}
<<quux.pl>>=
my #foo ;
my $bar ;
my %baz ;
# %def foo bar baz
\end{document}
and compiled using the commands:
$ noweb quux.nw
$ latexmk -pdf quux.tex
The identifiers bar and baz are properly highlighted as identifiers and cross referenced in the PDF output. The identifier foo is not.
It's my understanding that Noweb has a very simple heuristic for recognizing identifiers. foo should be recognizable as an identifier because, like bar and baz, it begins with an alphanumeric, is delimited on the left by a symbol (at-sign), and is delimited on the right by a delimiter (whitespace).
I considered the possibility that the at-sign was being interpreted by Noweb as an escape and tried doubling it, but that (i) did not solve the problem, and (ii) introduced the syntax error my ##foo into quux.pl. This makes sense because according to the fine manual, a double at-sign is only treated specially in columns 1–2.
Noweb treats # as alphanumeric, with the rationale that it “helps LaTeX”. I did not find anything about this in the Noweb manual. This is documented only in the Noweb source file finduses.nw, line 24, in Noweb version 2.12.
Apparently, when writing your own LaTeX package, any macro you define has public scope. To write “private” macros, the trick is to temporarily reclass the # as a letter at the top of the package, incorporate an # into the name of each “private” macro, and restore the class of # at the bottom of the package. The macro remains public, but is impossible to call because the name gets broken up into multiple lexemes. (A user can still call such a macro by reclassing # as a letter before the call, but if they do that, they assume the risk.)
So yes, # should be included as an alphanumeric character when the code block contains a LaTeX package.
The full list of symbols treated as alphanumeric by Noweb is:
_ ' # #
The _ is treated as an identifier character in many programming languages, so Noweb is right to treat it as alphanumeric.
The # is treated as alphanumeric to “avoid false hits on C preprocessor directives”.
No explanation is given for treating the ' as alphanumeric.
Ideally, Noweb would support separate character class schemes for each source language. But as I understand it, Noweb has only the one global character class scheme, and no support for changing it (other than modifying the source).
Fortunately, Perl has alternate syntaxes for array identifiers that work around this limitation. Instead of #foo you can write #{foo} or even # foo and it will work.

get symbol-name without uppercase

Is it possible in Common Lisp to get a symbol-name without the uppercase result?
(symbol-name 'aAbB)
;; => "AABB"
(OTHER_FUNCTION? 'aAbB)
;; => "aAbB"
I would like to use a symbol name as a string but case-sensitive.
Your symbol is actually all uppercase, because the reader already upcases it. In order to prevent that, you can either use a different readtable-case or escape the symbol, using either enclosing pipe symbols: '|aAbB| or a backslash for the next character: '\aA\bB.
There is quite a full answer on this question: Why is Common Lisp case insensitive
"The readtable objects has an attribute, readtable-case, that controls how the reader interns and evaluates the symbols read. you can setf readtable-case to :upcase(default), :downcase, :preserve, :invert.
By default, the readtable-case is set to :upcase, which causes all symbols to be converted to upcase."

.tmlanguage escape sequences and rule priorities

I'm implementing a syntax highlighter in Apple's Swift language by parsing .tmlanguage files and applying styles to a NSMutableAttributtedString.
I'm testing with javascript code, a javascript.tmlanguage file, and the monokai.tmtheme theme (both last included in sublime text 3) to check that the syntax get highlighted correctly. By applying each rule (patterns) in the .tmlanguage file in the same order they come, the syntax is almost perfectly highlighted.
The problem I'm having right now is that I don't know how to know that a quote (") should be escaped when it has a backslash before it (\"). Am I missing something in the .tmlanguage file that specifies that?. Other problem is that I have no idea how to know that other rules should be ignored when inside others, for example:
I'm getting double slashes taken as comments when inside strings: "http://stackoverflow.com/" a url is recognised as comment after //
Also double or single quotes are taken as strings when inside comments: // press "Enter" to continue, the word "Enter" gets highlighted as string when should be same color as comments
So, I don't know if there is some priority for some rules over others in the convention, or if there is something in the files that I haven't noticed.
Help please!
Update:
Here is a better example of what I meant by escape quotes:
I'm getting this: while all the letters should be yellow except for the escaped sequence (/") which should be blue.
The question is. How do I know that /" should be escaped? The rule for that piece of code is:
Maybe I am late to answer this. You can apply the following method.
(Ugly) In your end regex, use ([^/])(") and in your endCaptures, it would be
1 = string.quote.double.js
2 = punctuation.definition.string.end.js
If the string must be single line, you can use match=(")(.*)("), captures=
1 = punctuation.definition.string.begin.js
2 = string.quote.double.js
3 = punctuation.definition.string.end.js
and use your patterns
You can try applyEndPatternLast and see if it is allowed. Set applyEndPatternLast=1 will do.
The priority is that earlier rules in the file are prioritized over later rules. As an example, in my Python Improved language definition, I have a scope that contains a series of all-caps constants used in Django, a popular Python web framework. I also have a generic constant.other.allcaps.python scope that recognizes (just about) anything in all caps. Since the Django constants rule is before the allcaps rule in the .tmLanguage file, I can color it with a theme using one color, while the later-occurring "highlight everything in all caps" only grabs identifiers that are NOT part of the first list.
Because of this, you should put your "comments" scope(s) as early in the file as possible, then write your parser in such a way that it obeys the rule I described above. However, it's slightly more complicated than that, as I believe items in the repository are prioritized based on where their include line is, not where the repository rule is defined in the file. You may want to do some testing to verify that, though.
Unfortunately I'm not sure what you mean about the escaped quotes - could you expand on that, and maybe add an example or two?
Hope this helps.
Assuming that / is the correct character for escaping a double quote mark, the following should work:
"str_double_quote": {
"begin": "\"",
"end": "\"",
"name": "string.quoted.double.swift",
"patterns": [
{
"name": "constant.character.escape.swift",
"match": "/[\"/]"
}
]
}
You can match an escaped double quote mark (/") and a literal forward slash (//) in the patterns to consume them before the end marker is used to handle them.
If the character for escaping is actually a backslash, then the tricky bit is that there are two levels of escaping, for the JSON encoding as well as the regular expression syntax. To match \", the regular expression requires you to escape the backslash (\\"). JSON requires you to escape backslashes and double quotes, resulting in \\\\\" in a TextMate JSON grammar file. The match expression would thus be \\\\[\"\\\\].

How to escape double quote?

In org mode, if I want to format text a monospace verbatim, i.e. ~...~, if it is inside quotes: ~"..."~, it is not formatted (left as is).
Also, are quotes a reserved symbol, if so, what do they mean? (they don't seem to affect the generated HTML / inside Emacs display).
The culprit in this case is the regular expression in org-emph-re org-verbatim-re, responsible for determining if a sequence of characters in the document is to be set verbatim or not.
org-verbatim-re is a variable defined in `org.el'.
Its value is
"\([ ('\"{]\|^\)\(\([=~]\)\([^
\n,\"']\|[^
\n,\"'].?\(?:\n.?\)\{0,1\}[^
\n,\"']\)\3\)\([- .,:!?;'\")}\]\|$\)"
quotes and double quotes are explicitly forbidden inside verbatim characters =~ by
[^
\n,\"']\|[^
\n,\"']
I found discussions dating back 3 years comming to the conclusion that you have to tinker with this regular expression and set the variable org-emph-re/org-verbatim-re to something that matches your wishes in your emacs setup (maybe a file local variable works as well). You can experiment by excluding double quotes from the excluding character classes and outside matches as in
"\([ ('{]\|^\)\(\([*/_=~+]\)\([^
\n,']\|[^
\n,'].?\(?:\n.?\)\{0,1\}[^
\n,']\)\3\)\([- .,:!?;')}\]\|$\)"
but looking at that regex, heaven knows what happens to complex documents -- you have to try...
Edit: as it happens, if I evalute the following as region, quotes inside = are exported correctly, but nothing else is :-), I investigate further when I have more time.
(setq org-emph-re "\([ ('{]\|^\)\(\([*/_=~+]\)\([^
\n,']\|[^
\n,'].?\(?:\n.?\)\{0,1\}[^
\n,']\)\3\)\([- .,:!?;')}]\|$\)")
Edit 2:: Got it to work by changing org.el directly:
Change the line following (defvar org-emphasis-regexp-components from '(" \t('\"{" "- \t.,:!?;'\")}\\" " \t\r\n,\"'" "." 1) to '(" \t('{" "- \t.,:!?;')}\\" " \t\r\n,'" "." 1) and recompile org then restart emacs.
This was a defcustom prior to the 8.0 release, it isn't anymore, so you have to live with this manual modification.
regards,
Tom
Finally, I found a solution from http://comments.gmane.org/gmane.emacs.orgmode/82571
According to that thread, the regexp for verbatim is built from variable org-emphasis-regexp-components, which defines legal characters before, after, at the border of, or in the body of emphasis; and verbatim is one of the emphasis environment in org mode.
A workable setting given by that thread:
(setcar (nthcdr 2 org-emphasis-regexp-components) " \t\n,")
(custom-set-variables `(org-emphasis-alist ',org-emphasis-alist))
For small amounts of characters which have some unwanted effect in Emacs org-mode (because being metacharacters) it may be helpful to have a look at special symbols in org-mode (org-entities.el).
So for example " can be encoded by \quot{} (where the braces pair at the end is not mandatory, but needed if no whitespace follows).
So instead ="..."= you would write =\quot{}...\quot{}=.
That is some typing more and looks pretty ugly. But for the latter org-mode has a solution: by C-c C-x \ you can toggle a display magic for those symbols. If the magic is active, so directly after typing \quot{} resp. \quot{} a " will be displayed.
Besides, this symbols list can easily be extended, f.e.
(add-to-list 'org-entities
'("backslash" "\\textbackslash" nil "\\" "\\" "\\" "\\"))
Nevertheless I am heavily missing easier escaping in org-mode, besides the above solution and besides escaping a whole line by a : at its beginning.
I'd be happy if =verbatim= in all cases would leave the text between the ='s unchanged. Not =this*bold*text=, but =this *bold* text=. Like we know that from each well-designed markup/-down language.
But, of course, this is better placed at the org-mode development pages. Ideally with a fitting patch... :-)
I've met similar problem, and thanks #chaiko for a basic solution. However, #chaiko's solution only work for org-mode's fontification, it doesn't affect org-export. To get correct exported document, you need to do some more extra hack to org-mode's parser by (org-element--set-regexps).
So the full code snippets should be something like:
(setcar (nthcdr 2 org-emphasis-regexp-components) " \t\n\r")
(custom-set-variables `(org-emphasis-alist ',org-emphasis-alist))
(org-element--set-regexps)
I've integrated this to my oh-my-emacs project: https://github.com/xiaohanyu/oh-my-emacs/blob/e82fce10d47f7256df6d39e32ca288d0ec97a764/core/ome-org.org#code-block-fontification .

make m4 see macro when macro ends with same character as string following macro

I'm working on a system that uses M4 to expand some files out, but I'm getting a problem with the expansion in certain cases. The convention for definition / macro naming (which I'd rather not change if possible) is __<name>__ (i.e. double leading and trailing underscores.) So this expands correctly:
define(`__ROOT__', `/home/mydir')
...
__ROOT__/bin
gives
/home/mydir/bin
but,
define(`__PREFIX__', `App_Mnemonic')
...
__PREFIX___some_service
should give:
App_Mnemonic_some_service
but gives
__PREFIX___some_service
(i.e. it missed the expansion)
I presume the lack of space between the trailing underscore of the macro and the valid underscore of the underlying text is confusing m4. Is there anything I can do about this? Can I delimit the macro with silent braces, for example, like enviromnment variables?
Deceptively simple really, all I had to do in the underlying text was change this:
__PREFIX___some_service
for this:
__PREFIX__()_some_service
It looks a bit clunky perhaps, but it is a macro after all and there's no need to change the macro definition. So this can stay as it is:
define(`__PREFIX__', `App_Mnemonic')