" MetaPost indent file " Language: MetaPost " Maintainer: Nicola Vitacolonna <nvitacolonna@gmail.com> " Former Maintainers: Eugene Minkovskii <emin@mccme.ru> " Last Change: 2016 Oct 2, 4:13pm " Version: 0.2 if exists("b:did_indent") finish endif let b:did_indent = 1 setlocal indentexpr=GetMetaPostIndent() setlocal indentkeys+==end,=else,=fi,=fill,0),0] let b:undo_indent = "setl indentkeys< indentexpr<" " Only define the function once. if exists("*GetMetaPostIndent") finish endif let s:keepcpo= &cpo set cpo&vim function GetMetaPostIndent() let ignorecase_save = &ignorecase try let &ignorecase = 0 return GetMetaPostIndentIntern() finally let &ignorecase = ignorecase_save endtry endfunc " Regexps {{{ " Note: the next three variables are made global so that a user may add " further keywords. " " Example: " " Put these in ~/.vim/after/indent/mp.vim " " let g:mp_open_tag .= '\|\<begintest\>' " let g:mp_close_tag .= '\|\<endtest\>' " Expressions starting indented blocks let g:mp_open_tag = '' \ . '\<if\>' \ . '\|\<else\%[if]\>' \ . '\|\<for\%(\|ever\|suffixes\)\>' \ . '\|\<begingroup\>' \ . '\|\<\%(\|var\|primary\|secondary\|tertiary\)def\>' \ . '\|^\s*\<begin\%(fig\|graph\|glyph\|char\|logochar\)\>' \ . '\|[([{]' " Expressions ending indented blocks let g:mp_close_tag = '' \ . '\<fi\>' \ . '\|\<else\%[if]\>' \ . '\|\<end\%(\|for\|group\|def\|fig\|char\|glyph\|graph\)\>' \ . '\|[)\]}]' " Statements that may span multiple lines and are ended by a semicolon. To " keep this list short, statements that are unlikely to be very long or are " not very common (e.g., keywords like `interim` or `showtoken`) are not " included. " " The regex for assignments and equations (the last branch) is tricky, because " it must not match things like `for i :=`, `if a=b`, `def...=`, etc... It is " not perfect, but it works reasonably well. let g:mp_statement = '' \ . '\<\%(\|un\|cut\)draw\>' \ . '\|\<\%(\|un\)fill\%[draw]\>' \ . '\|\<draw\%(dbl\)\=arrow\>' \ . '\|\<clip\>' \ . '\|\<addto\>' \ . '\|\<save\>' \ . '\|\<setbounds\>' \ . '\|\<message\>' \ . '\|\<errmessage\>' \ . '\|\<errhelp\>' \ . '\|\<fontmapline\>' \ . '\|\<pickup\>' \ . '\|\<show\>' \ . '\|\<special\>' \ . '\|\<write\>' \ . '\|\%(^\|;\)\%([^;=]*\%('.g:mp_open_tag.'\)\)\@!.\{-}:\==' " A line ends with zero or more spaces, possibly followed by a comment. let s:eol = '\s*\%($\|%\)' " }}} " Auxiliary functions {{{ " Returns 1 if (0-based) position immediately preceding `pos` in `line` is " inside a string or a comment; returns 0 otherwise. " This is the function that is called more often when indenting, so it is " critical that it is efficient. The method we use is significantly faster " than using syntax attributes, and more general (it does not require " syntax_items). It is also faster than using a single regex matching an even " number of quotes. It helps that MetaPost strings cannot span more than one " line and cannot contain escaped quotes. function! s:CommentOrString(line, pos) let in_string = 0 let q = stridx(a:line, '"') let c = stridx(a:line, '%') while q >= 0 && q < a:pos if c >= 0 && c < q if in_string " Find next percent symbol let c = stridx(a:line, '%', q + 1) else " Inside comment return 1 endif endif let in_string = 1 - in_string let q = stridx(a:line, '"', q + 1) " Find next quote endwhile return in_string || (c >= 0 && c <= a:pos) endfunction " Find the first non-comment non-blank line before the current line. function! s:PrevNonBlankNonComment(lnum) let l:lnum = prevnonblank(a:lnum - 1) while getline(l:lnum) =~# '^\s*%' let l:lnum = prevnonblank(l:lnum - 1) endwhile return l:lnum endfunction " Returns true if the last tag appearing in the line is an open tag; returns " false otherwise. function! s:LastTagIsOpen(line) let o = s:LastValidMatchEnd(a:line, g:mp_open_tag, 0) if o == - 1 | return v:false | endif return s:LastValidMatchEnd(a:line, g:mp_close_tag, o) < 0 endfunction " A simple, efficient and quite effective heuristics is used to test whether " a line should cause the next line to be indented: count the "opening tags" " (if, for, def, ...) in the line, count the "closing tags" (endif, endfor, " ...) in the line, and compute the difference. We call the result the " "weight" of the line. If the weight is positive, then the next line should " most likely be indented. Note that `else` and `elseif` are both opening and " closing tags, so they "cancel out" in almost all cases, the only exception " being a leading `else[if]`, which is counted as an opening tag, but not as " a closing tag (so that, for instance, a line containing a single `else:` " will have weight equal to one, not zero). We do not treat a trailing " `else[if]` in any special way, because lines ending with an open tag are " dealt with separately before this function is called (see " GetMetaPostIndentIntern()). " " Example: " " forsuffixes $=a,b: if x.$ = y.$ : draw else: fill fi " % This line will be indented because |{forsuffixes,if,else}| > |{else,fi}| (3 > 2) " endfor function! s:Weight(line) let [o, i] = [0, s:ValidMatchEnd(a:line, g:mp_open_tag, 0)] while i > 0 let o += 1 let i = s:ValidMatchEnd(a:line, g:mp_open_tag, i) endwhile let [c, i] = [0, matchend(a:line, '^\s*\<else\%[if]\>')] " Skip a leading else[if] let i = s:ValidMatchEnd(a:line, g:mp_close_tag, i) while i > 0 let c += 1 let i = s:ValidMatchEnd(a:line, g:mp_close_tag, i) endwhile return o - c endfunction " Similar to matchend(), but skips strings and comments. " line: a String function! s:ValidMatchEnd(line, pat, start) let i = matchend(a:line, a:pat, a:start) while i > 0 && s:CommentOrString(a:line, i) let i = matchend(a:line, a:pat, i) endwhile return i endfunction " Like s:ValidMatchEnd(), but returns the end position of the last (i.e., " rightmost) match. function! s:LastValidMatchEnd(line, pat, start) let last_found = -1 let i = matchend(a:line, a:pat, a:start) while i > 0 if !s:CommentOrString(a:line, i) let last_found = i endif let i = matchend(a:line, a:pat, i) endwhile return last_found endfunction function! s:DecreaseIndentOnClosingTag(curr_indent) let cur_text = getline(v:lnum) if cur_text =~# '^\s*\%('.g:mp_close_tag.'\)' return max([a:curr_indent - shiftwidth(), 0]) endif return a:curr_indent endfunction " }}} " Main function {{{ " " Note: Every rule of indentation in MetaPost is very subjective. We might get " creative, but things get murky very soon (there are too many corner cases). " So, we provide a means for the user to decide what to do when this script " doesn't get it. We use a simple idea: use '%>', '%<' and '%=' to explicitly " control indentation. The '<' and '>' symbols may be repeated many times " (e.g., '%>>' will cause the next line to be indented twice). " " By using '%>...', '%<...' and '%=', the indentation the user wants is " preserved by commands like gg=G, even if it does not follow the rules of " this script. " " Example: " " def foo = " makepen( " subpath(T-n,t) of r %> " shifted .5down %> " --subpath(t,T) of r shifted .5up -- cycle %<<< " ) " withcolor black " enddef " " The default indentation of the previous example would be: " " def foo = " makepen( " subpath(T-n,t) of r " shifted .5down " --subpath(t,T) of r shifted .5up -- cycle " ) " withcolor black " enddef " " Personally, I prefer the latter, but anyway... function! GetMetaPostIndentIntern() " Do not touch indentation inside verbatimtex/btex.. etex blocks. if synIDattr(synID(v:lnum, 1, 1), "name") =~# '^mpTeXinsert$\|^tex\|^Delimiter' return -1 endif " This is the reference line relative to which the current line is indented " (but see below). let lnum = s:PrevNonBlankNonComment(v:lnum) " At the start of the file use zero indent. if lnum == 0 return 0 endif let prev_text = getline(lnum) " User-defined overrides take precedence over anything else. " See above for an example. let j = match(prev_text, '%[<>=]') if j > 0 let i = strlen(matchstr(prev_text, '%>\+', j)) - 1 if i > 0 return indent(lnum) + i * shiftwidth() endif let i = strlen(matchstr(prev_text, '%<\+', j)) - 1 if i > 0 return max([indent(lnum) - i * shiftwidth(), 0]) endif if match(prev_text, '%=', j) return indent(lnum) endif endif " If the reference line ends with an open tag, indent. " " Example: " " if c: " 0 " else: " 1 " fi if c2: % Note that this line has weight equal to zero. " ... % This line will be indented if s:LastTagIsOpen(prev_text) return s:DecreaseIndentOnClosingTag(indent(lnum) + shiftwidth()) endif " Lines with a positive weight are unbalanced and should likely be indented. " " Example: " " def f = enddef for i = 1 upto 5: if x[i] > 0: 1 else: 2 fi " ... % This line will be indented (because of the unterminated `for`) if s:Weight(prev_text) > 0 return s:DecreaseIndentOnClosingTag(indent(lnum) + shiftwidth()) endif " Unterminated statements cause indentation to kick in. " " Example: " " draw unitsquare " withcolor black; % This line is indented because of `draw`. " x := a + b + c " + d + e; % This line is indented because of `:=`. " let i = s:LastValidMatchEnd(prev_text, g:mp_statement, 0) if i >= 0 " Does the line contain a statement? if s:ValidMatchEnd(prev_text, ';', i) < 0 " Is the statement unterminated? return indent(lnum) + shiftwidth() else return s:DecreaseIndentOnClosingTag(indent(lnum)) endif endif " Deal with the special case of a statement spanning multiple lines. If the " current reference line L ends with a semicolon, search backwards for " another semicolon or a statement keyword. If the latter is found first, " its line is used as the reference line for indenting the current line " instead of L. " " Example: " " if cond: " draw if a: z0 else: z1 fi " shifted S " scaled T; % L " " for i = 1 upto 3: % <-- Current line: this gets the same indent as `draw ...` " " NOTE: we get here only if L does not contain a statement (among those " listed in g:mp_statement). if s:ValidMatchEnd(prev_text, ';'.s:eol, 0) >= 0 " L ends with a semicolon let stm_lnum = s:PrevNonBlankNonComment(lnum) while stm_lnum > 0 let prev_text = getline(stm_lnum) let sc_pos = s:LastValidMatchEnd(prev_text, ';', 0) let stm_pos = s:ValidMatchEnd(prev_text, g:mp_statement, sc_pos) if stm_pos > sc_pos let lnum = stm_lnum break elseif sc_pos > stm_pos break endif let stm_lnum = s:PrevNonBlankNonComment(stm_lnum) endwhile endif return s:DecreaseIndentOnClosingTag(indent(lnum)) endfunction " }}} let &cpo = s:keepcpo unlet s:keepcpo " vim:sw=2:fdm=marker