Added support for b option. Some snippets can be defined to only be valid at the beginning of the line

ChangeLog

@@ -1,4 +1,6 @@
 trunk:
+  - Added support for b option. This only considers a snippet at the beginning
+	 of a line ( *UltiSnips-adding-snippets* )
   - Added support for ! option. This overwrites previously defined snippets
     with the same tab trigger ( *UltiSnips-adding-snippets* )
   - Support for dotted filetype syntax. Now snippets for more than one filetype

UltiSnips/all.snippets

@@ -4,7 +4,7 @@
 ##############
 # NICE BOXES #
 ##############
-snippet box
+snippet box "A nice box with the current comment symbol" b
 `!p
 c = '#'
 cs = vim.eval("&commentstring")
@@ -21,7 +21,7 @@ res = ' ' + c + '\n' + (len(t[1])+4)*c`
 $0
 endsnippet
 
-snippet bbox
+snippet bbox "A nice box over the full width" b
 `!p
 c = '#'
 cs = vim.eval("&commentstring")

UltiSnips/help.snippets

@@ -1,6 +1,6 @@
 # Snippets for VIM Help Files
 
-snippet sec
+snippet sec "Section marker" b
 =============================================================================
 ${1:SECTION}`!p 
 file_start = fn.split('.')[0]
@@ -11,7 +11,7 @@ res = ("*%s-%s*" % (file_start, sec_name)).rjust(77-len(t[1]))`
 $0
 endsnippet
 
-snippet ssec
+snippet ssec "Sub section marker" b
 ${1:Subsection}`!p 
 file_start = fn.split('.')[0]
 sec_name = t[1].strip("1234567890. ").lower().replace(' ', '-')
@@ -22,7 +22,7 @@ res = sec_title + "\n" + "-"*len(t[1])`
 $0
 endsnippet
 
-snippet sssec
+snippet sssec "Subsub Section marker" b
  ${1:SubSubsection}:`!p 
 file_start = fn.split('.')[0]
 sec_name = t[1].strip("1234567890. ").lower().replace(' ', '-')

UltiSnips/python.snippets

@@ -3,13 +3,13 @@
 ###########################################################################
 
 #! header
-snippet #!
+snippet #! "Shebang header for python scripts" b
 #!/usr/bin/env python
 # encoding: utf-8
 $0
 endsnippet
 
-snippet ifmain "ifmain"
+snippet ifmain "ifmain" b
 if __name__ == '__main__':
     ${1:main()}$0
 endsnippet
@@ -18,7 +18,7 @@ endsnippet
 ##########
 # COMMON #
 ##########
-snippet class
+snippet class "smart class" b
 class ${1:MyClass}(${2:object}):
     """${3:Docstring for $1}"""
 
@@ -33,20 +33,20 @@ snippet .
 self.
 endsnippet
 
-snippet from
+snippet from "from blah import blah" b
 from ${1:module} import ${2:Stuff}
 endsnippet
 
 ##############
 # PROPERTIES #
 ##############
-snippet roprop
+snippet roprop "Read Only Property" b
 @property
 def ${1:property}(self):
     ${2:return self._$1}$0
 endsnippet
 
-snippet rwprop
+snippet rwprop "Read write property" b
 def ${1:property}(self):
     ${2/.+/(?0:""")/}${2:The RW property $1}${2/.+/(?0:"""\n    )/}def fget(self):
         return self._$1$0
@@ -59,14 +59,14 @@ endsnippet
 ##########################
 # Try / Except / Finally #
 ##########################
-snippet try "Try / Except"
+snippet try "Try / Except" b
 try:
     ${1:pass}
 except ${2:Exception}, ${3:e}:
     ${4:raise $3}
 endsnippet
 
-snippet try "Try / Except / Else"
+snippet try "Try / Except / Else" b
 try:
     ${1:pass}
 except ${2:Exception}, ${3:e}:
@@ -75,7 +75,7 @@ else:
     ${5:pass}
 endsnippet
 
-snippet try "Try / Except / Finally"
+snippet try "Try / Except / Finally" b
 try:
     ${1:pass}
 except ${2:Exception}, ${3:e}:
@@ -84,7 +84,7 @@ else:
     ${5:pass}
 endsnippet
 
-snippet try "Try / Except / Else / Finally"
+snippet try "Try / Except / Else / Finally" b
 try:
     ${1:pass}
 except${2: ${3:Exception}, ${4:e}}:
@@ -98,23 +98,23 @@ endsnippet
 ##############
 # Assertions #
 ##############
-snippet ae
+snippet ae "Assert equal" b
 self.assertEqual(${1:first},${2:second})
 endsnippet
 
-snippet at
+snippet at "Assert True" b
 self.assertTrue(${0:exp})
 endsnippet
 
-snippet af
+snippet af "Assert False" b
 self.assertFalse(${1:expression})
 endsnippet
 
-snippet aae
+snippet aae "Assert almost equal" b
 self.assertAlmostEqual(${1:first},${2:second})
 endsnippet
 
-snippet ar
+snippet ar "Assert raises" b
 self.assertRaises(${1:exception}, ${2:func}${3/.+/, /}${3:arguments})
 endsnippet
 

UltiSnips/tex.snippets

@@ -23,19 +23,19 @@ endsnippet
 ########################
 # ENUM, DESCR, ITEMIZE #
 ########################
-snippet enum
+snippet enum "Enumerate" b
 \begin{enumerate}
 	\item $0
 \end{enumerate}
 endsnippet
 
-snippet item
+snippet item "Itemize" b
 \begin{itemize}
 	\item $0
 \end{enumerate}
 endsnippet
 
-snippet desc
+snippet desc "Description" b
 \begin{description}
 	\item[$1] $0
 \end{description}
@@ -44,35 +44,35 @@ endsnippet
 ##############
 # MATH STUFF #
 ##############
-snippet eq "Equation"
+snippet eq "Equation" b
 \begin{equation}
 	$0
 \end{equation}
 endsnippet
 
-snippet eqnn "Equation without number"
+snippet eqnn "Equation without number" b
 \begin{equation*}
 	$0
 \end{equation*}
 endsnippet
 
-snippet eqa "Equation array"
+snippet eqa "Equation array" b
 \begin{eqnarray}
 	$1 & $2 & $0
 \end{eqnarray}
 endsnippet
 
-snippet eqann "Equation array without numbers"
+snippet eqann "Equation array without numbers" b
 \begin{eqnarray*}
 	$1 & $2 & $0
 \end{eqnarray*}
 
 endsnippet
-snippet frac
+snippet frac "Fraction"
 \frac{${1:nom}}{${2:denom}}
 endsnippet
 
-snippet mat
+snippet mat "Smart Matrix"
 \begin{${1:p/b/v/V/B/small}matrix}
 	$0
 \end{$1matrix}
@@ -83,7 +83,7 @@ endsnippet
 # SECTIONS, CHAPTERS AND THERE LIKE #
 #####################################
 
-snippet part
+snippet part "Part" b
 \part{${1:part name}}
 \label{prt:${2:${1/(\w+)|\W+/(?1:\L$0\E:_)/g}}}
 
@@ -92,7 +92,7 @@ ${0}
 % part $2 (end)
 endsnippet
 
-snippet cha
+snippet cha "Chapter" b
 \chapter{${1:chapter name}}
 \label{cha:${2:${1/\\\w+\{(.*?)\}|\\(.)|(\w+)|([^\w\\]+)/(?4:_:\L$1$2$3\E)/g}}}
 
@@ -101,7 +101,7 @@ ${0}
 % chapter $2 (end)
 endsnippet
 
-snippet sec
+snippet sec "Section" b
 \section{${1:section name}} 
 \label{sec:${2:${1/\\\w+\{(.*?)\}|\\(.)|(\w+)|([^\w\\]+)/(?4:_:\L$1$2$3\E)/g}}}
 
@@ -111,7 +111,7 @@ ${0}
 endsnippet
 
 
-snippet sub
+snippet sub "Subsection" b
 \subsection{${1:subsection name}}
 \label{sub:${2:${1/\\\w+\{(.*?)\}|\\(.)|(\w+)|([^\w\\]+)/(?4:_:\L$1$2$3\E)/g}}}
 
@@ -120,7 +120,7 @@ ${0}
 % subsection $2 (end)
 endsnippet
 
-snippet ssub
+snippet ssub "Subsubsection" b
 \subsubsection{${1:subsubsection name}}
 \label{ssub:${2:${1/\\\w+\{(.*?)\}|\\(.)|(\w+)|([^\w\\]+)/(?4:_:\L$1$2$3\E)/g}}}
 
@@ -130,7 +130,7 @@ ${0}
 
 endsnippet
 
-snippet par
+snippet par "Paragraph" b
 \paragraph{${1:paragraph name}}
 \label{par:${2:${1/\\\w+\{(.*?)\}|\\(.)|(\w+)|([^\w\\]+)/(?4:_:\L$1$2$3\E)/g}}}
 
@@ -140,7 +140,7 @@ ${0}
 endsnippet
 
 
-snippet subp
+snippet subp "Subparagraph" b
 \subparagraph{${1:subparagraph name}}
 \label{par:${2:${1/\\\w+\{(.*?)\}|\\(.)|(\w+)|([^\w\\]+)/(?4:_:\L$1$2$3\E)/g}}}
 

doc/UltiSnips.txt

@@ -157,7 +157,11 @@ snippet on. The options currently supported are >
        snippets with this tab trigger. Default is to let the user choose at
        expansion which snippet to expand. This option is useful to overwrite
        bundled tab stops with user defined ones.
-
+   b   Beginning of line - This snippet will only be expanded if you are at
+       the beginning of a line (that is if there are only whitespaces in front
+       of the cursor). Default is to expand snippets at every position, even
+       mitten in the line. Most of my snippets have this option set, it keeps
+       UltiSnips out of the way. 
 
 4.2 Plaintext snippets                         *UltiSnips-plaintext-snippets*
 ----------------------

plugin/UltiSnips/__init__.py

@@ -18,12 +18,16 @@ class Snippet(object):
         self._t = trigger
         self._v = value
         self._d = descr
-        self._overwrites = "!" in options
+        self._opts = options
 
     def overwrites_previous(self):
-        return self._overwrites
+        return "!" in self._opts
     overwrites_previous = property(overwrites_previous)
 
+    def needs_ws_in_front(self):
+        return "b" in self._opts
+    needs_ws_in_front = property(needs_ws_in_front)
+
     def description(self):
         return self._d
     description = property(description)
@@ -229,6 +233,11 @@ class SnippetManager(object):
                 snippets = snippets[idx:]
                 break
 
+        # Check if there are any only whitespace in front snippets
+        text_before = before.rstrip()[:-len(word)]
+        if text_before.strip(" \t") != '':
+            snippets = [ s for s in snippets if not s.needs_ws_in_front ]
+
         if not len(snippets):
             # No snippet found
             return False
@@ -259,7 +268,6 @@ class SnippetManager(object):
             else:
                 end = Position(pos.line - p_start.line, pos.col)
             start = Position(end.line, end.col - len(snippet.trigger))
-            text_before = vim.current.line[:pos.col - len(snippet.trigger)]
 
             si = snippet.launch(text_before, self._ctab, start, end)
 
@@ -269,7 +277,6 @@ class SnippetManager(object):
                 self._csnippets.append(si)
                 self.jump()
         else:
-            text_before = before.rstrip()[:-len(word)]
             self._vb = VimBuffer(text_before, after)
 
             start = Position(lineno-1, len(text_before))

test.py

@@ -978,7 +978,32 @@ class SnippetOptions_OverwriteThenChoose_ECR(_VimTest):
     )
     keys = "test" + EX + "1\n\n" + "test" + EX + "2\n"
     wanted = "We overwrite\nNo overwrite"
-
+class SnippetOptions_OnlyExpandWhenWSInFront_Expand(_VimTest):
+    snippets = ("test", "Expand me!", "", "b")
+    keys = "test" + EX
+    wanted = "Expand me!"
+class SnippetOptions_OnlyExpandWhenWSInFront_Expand2(_VimTest):
+    snippets = ("test", "Expand me!", "", "b")
+    keys = "   test" + EX
+    wanted = "   Expand me!"
+class SnippetOptions_OnlyExpandWhenWSInFront_DontExpand(_VimTest):
+    snippets = ("test", "Expand me!", "", "b")
+    keys = "a test" + EX
+    wanted = "a test"
+class SnippetOptions_OnlyExpandWhenWSInFront_OneWithOneWO(_VimTest):
+    snippets = (
+        ("test", "Expand me!", "", "b"),
+        ("test", "not at beginning", "", ""),
+    )
+    keys = "a test" + EX
+    wanted = "a not at beginning"
+class SnippetOptions_OnlyExpandWhenWSInFront_OneWithOneWOChoose(_VimTest):
+    snippets = (
+        ("test", "Expand me!", "", "b"),
+        ("test", "not at beginning", "", ""),
+    )
+    keys = "  test" + EX + "1\n"
+    wanted = "  Expand me!"
 
 ######################
 # SELECTING MULTIPLE #