review fixes

doc/UltiSnips.txt

@@ -655,9 +655,9 @@ The options currently supported are: >
        indentation too.
 
    e   Context snippets - With this option expansion of snippet can be
-       controlled not only by previous characters in line, but by any given python
-       expression. This option can be specified along with other options,
-       like 'b'. See |UltiSnips-context-snippets| for more info.
+       controlled not only by previous characters in line, but by any given
+       python expression. This option can be specified along with other
+       options, like 'b'. See |UltiSnips-context-snippets| for more info.
 
 The end line is the 'endsnippet' keyword on a line by itself. >
 
@@ -819,11 +819,11 @@ output is ignored.
 
 The variables automatically defined in python code are: >
 
-   fn   - The current filename
-   path - The complete path to the current file
-   t    - The values of the placeholders, t[1] is the text of ${1}, and so on
-   snip - UltiSnips.TextObjects.SnippetUtil object instance. Has methods that
-          simplify indentation handling.
+   fn      - The current filename
+   path    - The complete path to the current file
+   t       - The values of the placeholders, t[1] is the text of ${1}, etc.
+   snip    - UltiSnips.TextObjects.SnippetUtil object instance. Has methods
+             that simplify indentation handling.
    context - Result of context condition. See |UltiSnips-context-snippets|.
 
 The 'snip' object provides the following methods: >
@@ -1308,21 +1308,21 @@ In that case snippet should be defined using this syntax: >
 
     snippet tab_trigger "description" "expression" options
 
-'expression' can be any python expression. If 'expression' evaluates to
-'True', then this snippet will be chosen for expansion. 'expression' must be
-wrapped with double-quotes.
+The 'expression' can be any python expression. If 'expression' evaluates to
+'True', then this snippet will be chosen for expansion. The 'expression' must
+be wrapped with double-quotes.
 
-Following python modules are automatically imported: 're', 'os', 'vim',
-'string', 'random'.
+The following python modules are automatically imported into the scope before
+'expression' is evaluated: 're', 'os', 'vim', 'string', 'random'.
 
-Also, variables are declared in local scope for use in expression: >
+Also, the following variables are defined:
     'window' - alias for 'vim.current.window'
     'buffer' - alias for 'vim.current.window.buffer'
     'cursor' - alias for 'vim.current.cursor'
     'line' and 'column' - aliases for cursor position
 
 Keep in mind, that lines in vim numbered from 1, and lists in python starts
-from 0, so to access current line you need to use 'line-1' expression.
+from 0, so to access the current line you need to use 'line-1'.
 
 ------------------- SNIP -------------------
 snippet r "return" "re.match('^\s+if err ', buffer[line-2])" be
@@ -1330,7 +1330,7 @@ return err
 endsnippet
 ------------------- SNAP -------------------
 
-That snippet will expand to 'return err' only if previous line is starting
+That snippet will expand to 'return err' only if the previous line is starting
 from 'if err' prefix.
 
 Note: context snippets prioritized over non-context ones. So, if there are
@@ -1353,10 +1353,10 @@ endsnippet
 ------------------- SNAP -------------------
 
 That snippet will expand into 'if err != nil' if previous line will
-match 'err :=' prefix, otherwise default 'if' snippet will be expanded.
+match 'err :=' prefix, otherwise the default 'if' snippet will be expanded.
 
-It's good idea to move context conditions to separate library, so it can be
-used by other UltiSnips users. In that case, library should be imported
+It's good idea to move context conditions to a separate module, so it can be
+used by other UltiSnips users. In that case, module should be imported
 using 'global' keyword, like this:
 
 ------------------- SNIP -------------------
@@ -1372,15 +1372,15 @@ else:
 endsnippet
 ------------------- SNAP -------------------
 
-That snippet will expand only if cursor is located in the return statement,
-and then it will expand either to 'err' or to 'nil' depending in which 'if'
+That snippet will expand only if the cursor is located in the return statement,
+and then it will expand either to 'err' or to 'nil' depending on which 'if'
 statement it's located. 'is_return_argument' and 'is_in_err_condition' are
-part of custom python library which is called 'my_utils' in this example.
+part of custom python module which is called 'my_utils' in this example.
 
-Context condition can return any value which python can use as
-condition in it's 'if' statement, and if it's considired 'True', then snippet
-will be expanded. Moreover, result of condition will be accessed in the
-'context' variable:
+Context condition can return any value which python can use as condition in
+it's 'if' statement, and if it's considered 'True', then snippet will be
+expanded. The evaluated value of 'condition' is available in the 'context'
+variable inside the snippet:
 
 ------------------- SNIP -------------------
 snippet + "var +=" "re.match('\s*(.*?)\s*:?=', buffer[line-2])" ie

pythonx/UltiSnips/snippet/definition/_base.py

@@ -104,9 +104,7 @@ class SnippetDefinition(object):
             'column': current.window.cursor[1],
             'cursor': current.window.cursor,
         }
-
         exec(code, locals)
-
         return context["match"]
 
     def has_option(self, opt):
@@ -142,7 +140,7 @@ class SnippetDefinition(object):
 
     @property
     def context(self):
-        """Returns matched context."""
+        """The matched context."""
         return self._context
 
     def matches(self, trigger):

pythonx/UltiSnips/snippet_manager.py

@@ -476,7 +476,6 @@ class SnippetManager(object):
         elif feedkey:
             _vim.command('return %s' % _vim.escape(feedkey))
 
-    @err_to_scratch_buffer
     def _snips(self, before, partial):
         """Returns all the snippets for the given text before the cursor.
 

test/test_ContextSnippets.py

@@ -0,0 +1,87 @@
+from test.vim_test_case import VimTestCase as _VimTest
+from test.constant import *
+
+
+class ContextSnippets_SimpleSnippet(_VimTest):
+    files = { 'us/all.snippets': r"""
+        snippet a "desc" "True" e
+        abc
+        endsnippet
+        """}
+    keys = 'a' + EX
+    wanted = 'abc'
+
+
+class ContextSnippets_ExpandOnTrue(_VimTest):
+    files = { 'us/all.snippets': r"""
+        global !p
+        def check_context():
+            return True
+        endglobal
+
+        snippet a "desc" "check_context()" e
+        abc
+        endsnippet
+        """}
+    keys = 'a' + EX
+    wanted = 'abc'
+
+
+class ContextSnippets_DoNotExpandOnFalse(_VimTest):
+    files = { 'us/all.snippets': r"""
+        global !p
+        def check_context():
+            return False
+        endglobal
+
+        snippet a "desc" "check_context()" e
+        abc
+        endsnippet
+        """}
+    keys = 'a' + EX
+    wanted = keys
+
+
+
+class ContextSnippets_UseContext(_VimTest):
+    files = { 'us/all.snippets': r"""
+        global !p
+        def wrap(ins):
+            return "< " + ins + " >"
+        endglobal
+
+        snippet a "desc" "wrap(buffer[line-1])" e
+        { `!p snip.rv = context` }
+        endsnippet
+        """}
+    keys = 'a' + EX
+    wanted = '{ < a > }'
+
+
+class ContextSnippets_SnippetPriority(_VimTest):
+    files = { 'us/all.snippets': r"""
+        snippet i "desc" "re.search('err :=', buffer[line-2])" e
+        if err != nil {
+            ${1:// pass}
+        }
+        endsnippet
+
+        snippet i
+        if ${1:true} {
+            ${2:// pass}
+        }
+        endsnippet
+        """}
+
+    keys = r"""
+        err := some_call()
+        i""" + EX + JF +  """
+        i""" + EX
+    wanted = r"""
+        err := some_call()
+        if err != nil {
+            // pass
+        }
+        if true {
+            // pass
+        }"""