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I have created a guard snippet (ultisnips) in order to add on my existing functions:
snippet guard "add guard to functions" b
if !exists('*${1:func_name}')
${VISUAL}
endif
${0:jump here <C-j>}
endsnippet
At the moment I have to type the "func_name" at the top and it has to be equal at the name captured in the visual section, anyone have a better suggestion or any improvement to this?
Try this:
snippet guard "add guard to functions" b
if !exists('*`!p snip.rv = re.search('\S+\s+(\S+)\(', snip.v.text.splitlines()[0]).group(1)`')
${VISUAL}
endif
${0:jump here <C-j>}
endsnippet
The `!p snip.rv = ...` part is a python interpolation. The evaluation of the expression to the right of the assignment operator after snip.rv replaces everything between the backticks.
Here the expression is:
re.search('\S+\s+(\S+)\(', snip.v.text.splitlines()[0]).group(1)
snip.v.text allows you to refer to the last visually-selected text in a python interpolation..splitlines() allows you to split the lines of the visual selection in a list.
snip.v.text.splitlines()[0] grabs the first line in the selection.
re.search('\S+\s+(\S+)\(', ...).group(1) extracts the function name from this line.If you make a mistake when selecting the function, the first line may not match the regex, in which case an error will be raised.
Inside the python interpolation, you can use a try, except construct to catch the error:
snippet guard "add guard to functions" b
if !exists('*`!p
try:
func_name = re.search('\S+\s+(\S+)\(', snip.v.text.splitlines()[0]).group(1)
except AttributeError:
func_name = ''
snip.rv = func_name
`')
${VISUAL}
endif
${0:jump here <C-j>}
endsnippet
function or fun or functi, it must start with fu, so you could instead use r'\bfu\S*\s+(\S+)\(' to ensure it starts with 'fu' (and \b to prevent matching something like :Snafu). (There's lots of other possibilities for false positives, but this seems like the most important fix.)