Improve handling of multiline strings (#50)

* Improve handling of multiline strings

Fixes #49.

* tests: use an uneven width (3) instead of 8

This makes sure that the tests work as expected.

* tests: move helper functions to spec_helper.rb

* Add python_pep8_indent_for_multiline_string setting

Ref: #49 (comment)

* Use indent directly if prevnonblank is known

This removes the now unused s:indent_prevnonblank function.

Author: blueyed

README.rst

@@ -53,6 +53,28 @@ Follow the instructions on installing NeoBundle_ and add the appropriate NeoBund
    NeoBundle 'hynek/vim-python-pep8-indent'
 
 
+Configuration
+-------------
+
+python_pep8_indent_multiline_string
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+You can configure the initial indentation of multiline strings using ``g:python_pep8_indent_multiline_string`` (which can also be set per buffer).
+This defaults to ``0``, which means that multiline strings are not indented.
+``-1`` and positive values will be used as-is, where ``-1`` is a special value for Vim's ``indentexpr``, and will keep the existing indent (using Vim's ``autoindent`` setting).
+``-2`` is meant to be used for strings that are wrapped with ``textwrap.dedent`` etc.  It will add a level of indentation if the multiline string started in the previous line, without any content in it already::
+
+   testdir.makeconftest("""
+       _
+
+With content already, it will be aligned to the opening parenthesis::
+
+   testdir.makeconftest("""def pytest_addoption(parser):
+                        _
+
+Existing indentation (including ``0``) in multiline strings will be kept, so this setting only applies to the indentation of new/empty lines.
+
+
 Notes
 -----
 

indent/python.vim

@@ -32,6 +32,10 @@ setlocal tabstop=4
 setlocal softtabstop=4
 setlocal shiftwidth=4
 
+if !exists('g:python_pep8_indent_multiline_string')
+    let g:python_pep8_indent_multiline_string = 0
+endif
+
 let s:maxoff = 50
 let s:block_rules = {
             \ '^\s*elif\>': ['if', 'elif'],
@@ -333,28 +337,40 @@ function! s:is_python_string(lnum, ...)
 endfunction
 
 function! GetPythonPEPIndent(lnum)
-
     " First line has indent 0
     if a:lnum == 1
         return 0
     endif
 
     " Multilinestrings: continous, docstring or starting.
-    if s:is_python_string(a:lnum)
+    if s:is_python_string(a:lnum, 1)
+                \ && s:is_python_string(a:lnum-1, len(getline(a:lnum-1)))
+        " Keep existing indent.
+        if match(getline(a:lnum), '\v^\s*\S') != -1
+            return -1
+        endif
+
         if s:is_python_string(a:lnum-1)
             " Previous line is (completely) a string.
-            return s:indent_like_previous_line(a:lnum)
+            return indent(a:lnum-1)
         endif
 
         if match(getline(a:lnum-1), '^\s*\%("""\|''''''\)') != -1
             " docstring.
-            return s:indent_like_previous_line(a:lnum)
+            return indent(a:lnum-1)
         endif
 
-        if s:is_python_string(a:lnum-1, len(getline(a:lnum-1)))
-            " String started in previous line.
-            return 0
+        let indent_multi = get(b:, 'python_pep8_indent_multiline_string',
+                    \ get(g:, 'python_pep8_indent_multiline_string', 0))
+        if indent_multi != -2
+            return indent_multi
+        endif
+
+        if match(getline(a:lnum-1), '\v%("""|'''''')$') != -1
+            " Opening multiline string, started in previous line.
+            return indent(a:lnum-1) + s:sw()
         endif
+        return s:indent_like_opening_paren(a:lnum)
     endif
 
     " Parens: If we can find an open parenthesis/bracket/brace, line up with it.

spec/indent/indent_spec.rb

@@ -29,8 +29,8 @@
     before { vim.feedkeys '0ggipass' }
 
     it "does not indent" do
-      proposed_indent.should == 0
       indent.should == 0
+      proposed_indent.should == 0
     end
 
     it "does not indent when using '=='" do
@@ -161,68 +161,6 @@
     end
   end
 
-  describe "when after an '(' that is followed by an unfinished string" do
-    before { vim.feedkeys 'itest("""' }
-
-    it "it does not indent the next line" do
-      vim.feedkeys '\<CR>'
-      proposed_indent.should == 0
-      indent.should == 0
-    end
-
-    it "with contents it does not indent the next line" do
-      vim.feedkeys 'string_contents\<CR>'
-      proposed_indent.should == 0
-      indent.should == 0
-    end
-  end
-
-  describe "when after assigning an unfinished string" do
-    before { vim.feedkeys 'itest = """' }
-
-    it "it does not indent the next line" do
-      vim.feedkeys '\<CR>'
-      proposed_indent.should == 0
-      indent.should == 0
-    end
-  end
-
-  describe "when after assigning an unfinished string" do
-    before { vim.feedkeys 'i    test = """' }
-
-    it "it does not indent the next line" do
-      vim.feedkeys '\<CR>'
-      proposed_indent.should == 0
-      indent.should == 0
-    end
-  end
-
-  describe "when after assigning a finished string" do
-    before { vim.feedkeys 'i    test = ""' }
-
-    it "it does indent the next line" do
-      vim.feedkeys '\<CR>'
-      proposed_indent.should == 4
-      indent.should == 4
-    end
-
-    it "and writing a new string, it does indent the next line" do
-      vim.feedkeys '\<CR>""'
-      proposed_indent.should == 4
-      indent.should == 4
-    end
-  end
-
-  describe "when after a docstring" do
-    before { vim.feedkeys 'i    """' }
-
-    it "it does indent the next line" do
-      vim.feedkeys '\<CR>'
-      proposed_indent.should == 4
-      indent.should == 4
-    end
-  end
-
   describe "when using simple control structures" do
       it "indents shiftwidth spaces" do
           vim.feedkeys 'iwhile True:\<CR>pass'
@@ -436,43 +374,126 @@
       indent.should == shiftwidth * 2
     end
   end
+end
+
+shared_examples_for "multiline strings" do
+  describe "when after an '(' that is followed by an unfinished string" do
+    before { vim.feedkeys 'itest("""' }
 
-  def shiftwidth
-    @shiftwidth ||= vim.echo("exists('*shiftwidth') ? shiftwidth() : &sw").to_i
+    it "it indents the next line" do
+      vim.feedkeys '\<CR>'
+      expected_proposed, expected_indent = multiline_indent(0, shiftwidth)
+      proposed_indent.should == expected_proposed
+      indent.should == expected_indent
+    end
+
+    it "with contents it indents the second line to the parenthesis" do
+      vim.feedkeys 'second line\<CR>'
+      expected_proposed, expected_indent = multiline_indent(0, 5)
+      proposed_indent.should == expected_proposed
+      indent.should == expected_indent
+    end
+  end
+
+  describe "when after assigning an unfinished string" do
+    before { vim.feedkeys 'itest = """' }
+
+    it "it indents the next line" do
+      vim.feedkeys '\<CR>'
+      expected_proposed, expected_indent = multiline_indent(0, shiftwidth)
+      proposed_indent.should == expected_proposed
+      indent.should == expected_indent
+    end
   end
-  def tabstop
-    @tabstop ||= vim.echo("&tabstop").to_i
+
+  describe "when after assigning an unfinished string" do
+    before { vim.feedkeys 'i    test = """' }
+
+    it "it indents the next line" do
+      vim.feedkeys '\<CR>'
+      expected_proposed, expected_indent = multiline_indent(4, shiftwidth + 4)
+      proposed_indent.should == expected_proposed
+      indent.should == expected_indent
+    end
   end
-  def indent
-    vim.echo("indent('.')").to_i
+
+  describe "when after assigning a finished string" do
+    before { vim.feedkeys 'i    test = ""' }
+
+    it "it does indent the next line" do
+      vim.feedkeys '\<CR>'
+      indent.should == 4
+    end
+
+    it "and writing a new string, it does indent the next line" do
+      vim.feedkeys '\<CR>""'
+      indent.should == 4
+    end
   end
-  def previous_indent
-    pline = vim.echo("line('.')").to_i - 1
-    vim.echo("indent('#{pline}')").to_i
+
+  describe "when after a docstring" do
+    before { vim.feedkeys 'i    """' }
+    it "it does indent the next line to the docstring" do
+      vim.feedkeys '\<CR>'
+      indent.should == 4
+      proposed_indent.should == 4
+    end
   end
-  def proposed_indent
-    line = vim.echo("line('.')")
-    col = vim.echo("col('.')")
-    indent_value = vim.echo("GetPythonPEPIndent(line('.'))").to_i
-    vim.command("call cursor(#{line}, #{col})")
-    return indent_value
+
+  describe "when after a docstring with contents" do
+    before { vim.feedkeys 'i    """First line' }
+    it "it does indent the next line to the docstring" do
+      vim.feedkeys '\<CR>'
+      indent.should == 4
+      proposed_indent.should == 4
+    end
   end
 end
 
 describe "vim when using width of 4" do
   before {
     vim.command("set sw=4 ts=4 sts=4 et")
   }
+  it_behaves_like "vim"
+end
 
+describe "vim when using width of 3" do
+  before {
+    vim.command("set sw=3 ts=3 sts=3 et")
+  }
   it_behaves_like "vim"
 end
 
-describe "vim when using width of 8" do
+describe "vim when not using python_pep8_indent_multiline_string" do
   before {
-    vim.command("set sw=8 ts=8 sts=8 et")
+    vim.command("set sw=4 ts=4 sts=4 et")
+    vim.command("unlet! g:python_pep8_indent_multiline_string")
   }
+  it_behaves_like "multiline strings"
+end
 
-  it_behaves_like "vim"
+describe "vim when using python_pep8_indent_multiline_first=0" do
+  before {
+    vim.command("set sw=4 ts=4 sts=4 et")
+    vim.command("let g:python_pep8_indent_multiline_string=0")
+  }
+  it_behaves_like "multiline strings"
+end
+
+describe "vim when using python_pep8_indent_multiline_string=-1" do
+  before {
+    vim.command("set sw=4 ts=4 sts=4 et")
+    vim.command("let g:python_pep8_indent_multiline_string=-1")
+  }
+  it_behaves_like "multiline strings"
+end
+
+describe "vim when using python_pep8_indent_multiline_string=-2" do
+  before {
+    vim.command("set sw=4 ts=4 sts=4 et")
+    vim.command("let g:python_pep8_indent_multiline_string=-2")
+  }
+  it_behaves_like "multiline strings"
 end
 
 describe "vim for cython" do
@@ -482,16 +503,6 @@ def proposed_indent
     vim.command "runtime indent/python.vim"
   }
 
-  def shiftwidth
-    @shiftwidth ||= vim.echo("exists('*shiftwidth') ? shiftwidth() : &sw").to_i
-  end
-  def tabstop
-    @tabstop ||= vim.echo("&tabstop").to_i
-  end
-  def indent
-    vim.echo("indent('.')").to_i
-  end
-
   describe "when using a cdef function definition" do
       it "indents shiftwidth spaces" do
           vim.feedkeys 'icdef long_function_name(\<CR>arg'

spec/spec_helper.rb

@@ -22,6 +22,31 @@
     vim.command "runtime syntax/python.vim"
     vim.command "runtime indent/python.vim"
 
+    def shiftwidth
+      @shiftwidth ||= vim.echo("exists('*shiftwidth') ? shiftwidth() : &sw").to_i
+    end
+    def tabstop
+      @tabstop ||= vim.echo("&tabstop").to_i
+    end
+    def indent
+      vim.echo("indent('.')").to_i
+    end
+    def previous_indent
+      pline = vim.echo("line('.')").to_i - 1
+      vim.echo("indent('#{pline}')").to_i
+    end
+    def proposed_indent
+      line = vim.echo("line('.')")
+      col = vim.echo("col('.')")
+      indent_value = vim.echo("GetPythonPEPIndent(line('.'))").to_i
+      vim.command("call cursor(#{line}, #{col})")
+      return indent_value
+    end
+    def multiline_indent(prev, default)
+      i = vim.echo("get(g:, 'python_pep8_indent_multiline_string', 0)").to_i
+      return (i == -2 ? default : i), i < 0 ? (i == -1 ? prev : default) : i
+    end
+
     vim
   end
 end