Inherit the indent of the previous element at the same sexp level

The builtin 'lisp' indenter does this.

See src/misc1.c:get_lisp_indent()

Includes test case!

Addresses #47

Author: guns

clj/dev-resources/test-inherit-indent.in

@@ -0,0 +1,3 @@
+(foo bar [✖])
+
+;; vim:ft=clojure:

clj/dev-resources/test-inherit-indent.out

@@ -0,0 +1,7 @@
+(foo bar [
+  a
+  b
+  
+  c])
+
+;; vim:ft=clojure:

clj/test/vim_clojure_static/indent_test.clj

@@ -0,0 +1,9 @@
+(ns vim-clojure-static.indent-test
+  (:require [clojure.test :refer [deftest]]
+            [vim-clojure-static.test :refer [test-indent]]))
+
+(deftest test-indentation
+  (test-indent "is inherited from previous element"
+               :in "test-inherit-indent.in"
+               :out "test-inherit-indent.out"
+               :keys "/✖\\<Esc>s\\<CR>\\<C-H>\\<C-H>\\<C-H>\\<C-H>a\\<CR>b\\<CR>\\<CR>c\\<Esc>"))

indent/clojure.vim

@@ -192,17 +192,23 @@ if exists("*searchpairpos")
 		return val
 	endfunction
 
-	function! GetClojureIndent()
+	" Returns 1 for opening brackets, -1 for _anything else_.
+	function! s:bracket_type(char)
+		return stridx('([{', a:char) > -1 ? 1 : -1
+	endfunction
+
+	" Returns: [opening-bracket-lnum, indent]
+	function! s:clojure_indent_pos()
 		" Get rid of special case.
 		if line(".") == 1
-			return 0
+			return [0, 0]
 		endif
 
 		" We have to apply some heuristics here to figure out, whether to use
 		" normal lisp indenting or not.
 		let i = s:check_for_string()
 		if i > -1
-			return i + !!g:clojure_align_multiline_strings
+			return [0, i + !!g:clojure_align_multiline_strings]
 		endif
 
 		call cursor(0, 1)
@@ -219,19 +225,19 @@ if exists("*searchpairpos")
 		" curly indent.
 		if curly[0] > bracket[0] || curly[1] > bracket[1]
 			if curly[0] > paren[0] || curly[1] > paren[1]
-				return curly[1]
+				return curly
 			endif
 		endif
 
 		" If the curly was not chosen, we take the bracket indent - if
 		" there was one.
 		if bracket[0] > paren[0] || bracket[1] > paren[1]
-			return bracket[1]
+			return bracket
 		endif
 
 		" There are neither { nor [ nor (, ie. we are at the toplevel.
 		if paren == [0, 0]
-			return 0
+			return paren
 		endif
 
 		" Now we have to reimplement lispindent. This is surprisingly easy, as
@@ -250,12 +256,12 @@ if exists("*searchpairpos")
 		call cursor(paren)
 
 		if s:is_method_special_case(paren)
-			return paren[1] + &shiftwidth - 1
+			return [paren[0], paren[1] + &shiftwidth - 1]
 		endif
 
 		" In case we are at the last character, we use the paren position.
 		if col("$") - 1 == paren[1]
-			return paren[1]
+			return paren
 		endif
 
 		" In case after the paren is a whitespace, we search for the next word.
@@ -267,14 +273,14 @@ if exists("*searchpairpos")
 		" If we moved to another line, there is no word after the (. We
 		" use the ( position for indent.
 		if line(".") > paren[0]
-			return paren[1]
+			return paren
 		endif
 
 		" We still have to check, whether the keyword starts with a (, [ or {.
 		" In that case we use the ( position for indent.
 		let w = s:current_word()
-		if stridx('([{', w[0]) > -1
-			return paren[1]
+		if s:bracket_type(w[0]) == 1
+			return paren
 		endif
 
 		" Test words without namespace qualifiers and leading reader macro
@@ -284,23 +290,67 @@ if exists("*searchpairpos")
 		let ww = s:strip_namespace_and_macro_chars(w)
 
 		if &lispwords =~# '\V\<' . ww . '\>'
-			return paren[1] + &shiftwidth - 1
+			return [paren[0], paren[1] + &shiftwidth - 1]
 		endif
 
 		if g:clojure_fuzzy_indent
 			\ && !s:match_one(g:clojure_fuzzy_indent_blacklist, ww)
 			\ && s:match_one(g:clojure_fuzzy_indent_patterns, ww)
-			return paren[1] + &shiftwidth - 1
+			return [paren[0], paren[1] + &shiftwidth - 1]
 		endif
 
 		call search('\v\_s', 'cW')
 		call search('\v\S', 'W')
 		if paren[0] < line(".")
-			return paren[1] + (g:clojure_align_subforms ? 0 : &shiftwidth - 1)
+			return [paren[0], paren[1] + (g:clojure_align_subforms ? 0 : &shiftwidth - 1)]
 		endif
 
 		call search('\v\S', 'bW')
-		return virtcol(".") + 1
+		return [line('.'), virtcol('.') + 1]
+	endfunction
+
+	function! GetClojureIndent()
+		let lnum = line('.')
+		let [opening_lnum, indent] = s:clojure_indent_pos()
+
+		" Return if there are no previous lines to inherit from
+		if opening_lnum < 1 || opening_lnum >= lnum - 1
+			return indent
+		endif
+
+		let bracket_count = 0
+
+		" Take the indent of the first previous non-white line that is
+		" at the same sexp level. cf. src/misc1.c:get_lisp_indent()
+		while 1
+			let lnum = prevnonblank(lnum - 1)
+			let col = 1
+
+			if lnum <= opening_lnum
+				break
+			endif
+
+			call cursor(lnum, col)
+
+			" Handle bracket counting edge case
+			if s:is_paren()
+				let bracket_count += s:bracket_type(s:current_char())
+			endif
+
+			while 1
+				if search('\v[(\[{}\])]', '', lnum) < 1
+					break
+				elseif !s:ignored_region()
+					let bracket_count += s:bracket_type(s:current_char())
+				endif
+			endwhile
+
+			if bracket_count == 0
+				return indent(lnum)
+			endif
+		endwhile
+
+		return indent
 	endfunction
 
 	setlocal indentexpr=GetClojureIndent()