What is the best way to create control flow in templates? - templates

I am working on making my own "language/template" that "compiles" to another "language" called mcfunction. The main reasoning for this being that mcfunction does not contain loops or lambdas, so I essentially just want to add those two features to it. I am doing this by creating my own file extension and having a program I run convert my own custom syntax into syntax that makes sense to the mcfunction "language".
I've been mostly successful but adding the looping system I want has been difficult, and I wanted to know if there was a better way to do it than I currently am. My dad suggested I use a template, but I have no idea how that works and looking up how to do it I couldn't really find anything that helps.
Basically, the Syntax I want to implement is something like
[('foo','bar'),('baz','qux'),('quux','quz')](
say {1}
tellraw #a "{2}, {1}"
)
into
say foo
tellraw #a "bar, foo"
say baz
tellraw #a "qux, baz"
say quux
tellraw #a "quz, quux"
I need to replace every instance of this syntax in a giant string with the output there and ideally be able to escape single quotes, and put the input on multiple lines.
so
[
('foo','bar'),
('baz','qux'),
('quux','quz')
](
say {1}
tellraw #a "{2}, {1}"
)
should output the same thing.
I started working on a mess of a regex to handle this for me or break it down to help me, but my dad told me a templating engine might help and I couldn't figure out how to make that work so I came here for help. Thanks for reading this.

Related

Scanning a language with non-delimited strings with nested tokens

I want to create a lexer/parser for a language that has non-delimited strings.
Which part of the language is a string is defined by the command preceding it.
For example it has statements that look like this:
pause 5
alert Hello world[CRLF] this contains 'pause' once (1)
Alert in this instance can end with any string, including keywords and numbers.
Further complicating things, the text can contain tags like [CRLF] that I want to separate too.
Ideally I'd want this to be broken up into:
[PAUSE][INT 5]
[ALERT][STR "Hello world"][CRLF][STR " this contains 'pause' once (1)"]
I'm currently using flex but from what I've gathered this kind of thing isn't possible with flex.
How can I achieve what I want here?
(Since one of your tags is "regex", I'll suggest a non-flex approach.)
From the example, it seems like you could just:
match each line against ^(\w+) (.+) to obtain command and arguments-text, and then
get individual arguments by splitting the arguments-text on (\[\w+\]) (assuming your regex library's split function can return both the splitter-strings and the split-strings).
It's possible your actual situation is more complex and something like flex makes more sense, but I'm not really seeing it so far.

Conditional RegExp Replace - if reference is found, then write something else

Two cases
1. Key<A, M> desc = newKey();
2. Property<B, N> type = newKey("type", B.bar);
The RegExp and replace
find: (?:Key|Property)<(.*), (.*)> (.*) = newKey\((.*)\);
rep.: Foo<C$1, $2> $3 = pl.nP("$3", $2.class); // ($4)
The Result
1. Foo<CA, M> desc = pl.nP("desc", M.class); //
2. Foo<CB, N> type = pl.nP("type", N.class); // ("type", B.bar)
The Problem:
Now I want to avoid the empty comment at the line 1.
Is there a way to write the $4 and the stuff around it only if $4
isn't empty?
You could remove empty comments afterwards with another regular expression.
EDIT
Another solution would be to deal with the special case separately (... = newKey\(\)).
Perhaps you could automate this process with a simple script, if the tedium of repetitive typing becomes too great(eg. when dealing with multiple conditionals).
As far as I know, there isn't any 'intelligence' built into the replace field in Sublime Text; all you can do is to assemble the captured pieces to your liking.
While skimming through a few Google search results yesterday, I found an article about conditional patterns in Perl, but nothing pertaining to the problem at hand.
For the sake of full disclosure, I should say that I am in no sense an expert in the field, so I could be wrong. I do however have some experience with the Python API for
Sublime Text. It might be possible to implement this functionality yourself, if it doesn't already exist within the plethora of extensions available.
I'm sorry if this sounds like a very long-winded 'uh uh', but I'll be on the lookout for a general solution.

vim abbreviations and regular expressions

In vim, is it possible to use regular expressions in abbreviations? For example, something like
:iab \([0-9]\{-}\)nm \\SI{\1}{\\nano\\meter}
would would expand every instance of, say, '50nm' to '\SI{50}{\nano\meter}'.
Your best bet is to write a little helper function to yourself. Tapping into omni completion or the user defined completion (C-x C-u, see :help 'cfu') is a good choice. I sketched a regular function to imap on a key:
function! ExpandNanometers()
let items = matchlist(expand('<cword>'), '\v(\d+)nm')
if len(items) == 0
return
endif
let modified = '\SI{' . items[1] . '}{\nano\meter}'
exec "normal! ciw" . modified
endf
imap <C-l> <C-o>:call ExpandNanometers()<CR>
Not the best code, perhaps. Bound on insert-mode C-l, it will replace words such as 50nm to the desired if the cursor is on the word or directly after it.
I wanted to add this as a comment to the previous answer, but apparently I can't until 50 rep. I also know this is wayyy too late, but for reference purposes:
If key mappings are acceptable (going by the prev. answer), surely something like
imap <silent> <leader>obscure-key-of-choice <Esc>:%s/\v(\d+)nm/\\SI{\1}{\\nano\\meter}/g<CR>``i
(i.e. global substitute on the whole file with the desired patterns)
would be easier to maintain? I like to avoid vimscript for readability/maintenance of the .vimrc! Obviously you replace obscure-key-of-choice by your obscure key of choice. You only have to do it once after having typed all the text anyway, so better save the other keys for more conventionally useful bindings!
The shortcut replaces something like
50nm blabla 73nm your-interesting-science-here 89nm
... some new lines...
we love nanometers nm! 34nm and finally 18nm
with something like
\SI{50}{\nano\meter} blabla \SI{73}{\nano\meter} your-interesting-science-here \SI{89}{\nano\meter}
... some new lines...
we love nanometers nm! \SI{34}{\nano\meter} and finally \SI{18}{\nano\meter}

Highlighting Javascript Inline Block Comments in Vim

Background
I use JScript (Microsoft's ECMAScript implementation) for a lot of Windows system administration needs. This means I use a lot of ActiveX (Automated COM) objects. The methods of these objects often expect Number or Boolean arguments. For example:
var fso = new ActiveXObject("Scripting.FileSystemObject");
var a = fso.CreateTextFile("c:\\testfile.txt", true);
a.WriteLine("This is a test.");
a.Close();
(CreateTextFile Method on MSDN)
On the second line you see that the second argument is one that I'm talking about. A Boolean of "true" doesn't really describe how the method's behavior will change. This isn't a problem for me, but my automation-shy coworkers are easily spooked. Not knowing what an argument does spooks them. Unfortunately a long list of constants (not real constants, of course, since current JScript versions don't support them) will also spook them. So I've taken to documenting some of these basic function calls with inline block comments. The second line in the above example would be written as such:
var a = fso.CreateTextFile("c:\\testfile.txt", /*overwrite*/ true, /*unicode*/ false);
That ends up with a small syntax highlighting dilemma for me, though. I like my comments highlighted vibrantly; both block and line comments. These tiny inline block comments mean little to me, personally, however. I'd like to highlight those particular comments in a more muted fashion (light gray on white, for example). Which brings me to my dilemma.
Dilemma
I'd like to override the default syntax highlighting for block comments when both the beginning and end marks are on the same line. Ideally this is done solely in my vimrc file, and not in a superseding personal copy of the javascript.vim syntax. My initial attempt is pathetic:
hi inlineComment guifg=#bbbbbb
match inlineComment "\/\*.*\*\/"
Straight away you can see the first problem with this regular expression pattern is that it's a greedy search. It's going to match from the first "/*" to the last "*/" on the line, meaning everything between two inline block comments will get this highlight style as well. I can fix that, but I'm really not sure how to deal with my second concern.
Comments can't be defined inside of String literals in ECMAScript. So this syntax highlighting will override String highlighting as well. I've never had a problem with this in system administration scripts, but it does often bite me when I'm examining the source of many javascript libraries intended for browsers (less.js for example).
What regex pattern, syntax definition, or other solution would the amazing StackOverflow community recommend to restore my vimrc zen?
I'm not sure, but from your description it sounds like you don't need a new syntax definition. Vim syntax files usually let you override a particular syntax item with your own choice of highlighting. In this case, the item you want is called javaScriptComment, so a command like this will set its highlighting:-
hi javaScriptComment guifg=#bbbbbb
but you have to do this in your .vimrc file (or somewhere that's sourced from there), so it's evaluated before the syntax file. The syntax file uses the highlight default command, so the syntax file's choice of highlighting only affects syntax items with no highlighting set. See :help :hi-default for more details on that. BTW, it only works on Vim 5.8 and later.
The above command will change all inline /* */ comments, and leave // line comments with their default setting, because line comments are a different syntax item (javaScriptLineComment). You can find the names of all these groups by looking at the javascript.vim file. (The easiest way to do this is :e $VIMRUNTIME/syntax/javascript.vim .)
If you only want to change some inline comments, it's a little more complicated, but still easy to see what to do by looking at javascript.vim . If you do that, you can see that block comments are defined like this:-
syn region javaScriptComment start="/\*" end="\*/" contains=#Spell,javaScriptCommentTodo
See that you can use separate regexes for begin and end markers: you don't need to worry about matching the stuff in between with non-greedy quantifiers, or anything like that. To have a syntax item that works similarly but only on one line, try adding the oneline option (:h :syn-oneline for more details):-
syn region myOnelineComment start="/\*" end="\*/" oneline
I've removed the two contains groups because (1) if you're only using it for parameter names, you probably don't want spell-checking turned on inside these comments, and (2) contained sections that aren't oneline override the oneline in the container region, so you would still match all TODO comments with this region.
You can define this new kind of comment region in your .vimrc, and set the highlighting how you like: it looks like you already know how to do that, so I won't go into more details on that. I haven't tried out this particular example, so you may still need a bit of fiddling to make it work. Give it a try and let me know how it goes.
Why don't you simply add a comment line above the call?
I think that
// fso.CreateTextFile(filename:String, overwrite:Boolean, unicode:Boolean)
var a = fso.CreateTextFile("c:\\testfile.txt", true, false);
is a lot more readable and informative than
var a = fso.CreateTextFile("c:\\testfile.txt", /*overwrite*/ true, /*unicode*/ false);

Vim, C++, look up member function

I am using vim 7.x
I am using alternate file.
I have a mapping of *.hpp <--> *.cpp
Suppose I'm in
class Foo {
void some_me#mber_func(); // # = my cursor
}
in Foo.hpp
is there a way to tell vim to do the following:
Grab word under # (easy, expand("")
Look up the class I'm inside of ("Foo") <-- I have no idea how to do this
Append `1 & 2 (easy: using ".") --> "Foo::some_member_func"
4: Switch files (easy, :A)
Do a / on 4
So basically, I can script all of this together, except the "find the name of the enclosing class I'm in part (especially if classes are nested).
I know about ctags. I know about cscope. I'm choosing to not use them -- I prefer solutions where I understand where they break.
This is relatively easy to do crudely and very difficult to do well. C and C++ are rather complex languages to parse reliably. At the risk of being downvoted, I'd personally recommend parsing the tags file generated by ctags, but if you really want to do it in Vim, there are a few of options for the "crude" method.
Make some assumptions. The assumptions you make depend on how complicated you want it to be. At the simplest level: assume you're in a class definition and there are no other nearby braces. Based on your coding style, assume that the opening brace of the class definition is on the same line as "class".
let classlineRE = '^class\s\+\(\k\+\)\s\+{.*'
let match = search(classlineRE, 'bnW')
if match != 0
let classline = getline(match)
let classname = substitute(classline, classlineRE, '\1', '')
" Now do something with classname
endif
The assumptions model can obviously be extended/generalised as much as you see fit. You can just search back for the brace and then search back for class and take what's in between (to handle braces on a separate line to "class"). You can filter out comments. If you want to be really clever, you can start looking at what level of braces you're in and make sure it's a top level one (go to the start of the file, add 1 every time you see '{' and subtract one every time you see '}' etc). Your vim script will get very very very complicated.
Another one risking the downvote, you could use one of the various C parsers written in python and use the vim-python interface to make it act like a vim script. To be honest, if you're thinking of doing this, I'd stick with ctags/cscope.
Use rainbow.vim. This does highlighting based on depth of indentation, so you could be a little clever and search back (using search('{', 'bW') or similar) for opening braces, then interrogate the syntax highlighting of those braces (using synIDattr(synID(line("."), col("."),1), "name")) and if it's hlLevel0, you know it's a top-level brace. You can then search back for class and parse as per item 1.
I hope that all of the above gives you some food for thought...