SnippetMode

What snippet is

snippet.el is a templating system by Pete Kazmier similar to the one reported to be found in the proprietary OSX editor TextMate. A snippet is defined as a string that has special instructions inside.

Explanation

All instructions begin with a dollar sign ($).

$${default}
Creates a field that one can leave as is, or change. One can (BACK)TAB through fields
If there are multiple occurrences of the same default value, all of these will change
along. This comes in handy when such a default value is a variable in the code that
you want to write.
$>
Calls ‘indent-according-to-mode’ at that point.
$.
Specifies endpoint of snippet, i.e. where you end up when there are no more fields.

Examples

Here’s an example snippet for a typical for-loop in JavaScript to see the instructions in action:

    "$>for (var $${i}=$${0},$${len}=$${i}.length;$${i}<$${len};++$${i}){\n$>$.\n}$>"

which expands to:

    for (var i=0,len=i.length;i<len;++i){
        .  
    }

The dot in the body will not show, but indicates the endpoint of the snippet.

Here’s an example of a setup of snippet for javascript-mode:

    (require 'snippet)
    (define-abbrev-table 'javascript-mode-abbrev-table ())
    (snippet-with-abbrev-table
     'javascript-mode-abbrev-table
     ("for" .  "$>for (var $${i}=$${0},$${len}=$${i}.length;$${i}<$${len};++$${i}){\n$>$.\n}$>")
     ("forin" . "$>for (var $${i} in $${var}){\n$>$$;\n}$.$>")
     ("if"  .  "$>if ($${cond}){$>\n$>$.;\n}$>")
     ("ifel" . "$>if ($${cond}){$>\n$>$$;\n} else {$>\n$>$$;\n}$.$>")
     ("wh"  .  "$>while ($${i}){\n$>$.\n}$>")
     ("whinc" . "$>while ($${i}<$${10}){\n$>$.\n$>$${i}++;\n}$>")
     ("trn" . "$${if}?$${then}:$${else}")
     ("var" . "var $${variable} = $${value};")
     ("fun" . "$>function $${name}($${args}){\n$>$.\n}$>")
     ("lambda" . "$>function ($${args}){\n$>$.\n}$>")
     ("df" . "document.forms['$${formname}']")
     ("cl" . "console.log('$${message}');")) ;Firebug logging 
    (add-hook 'javascript-mode-hook
              (lambda ()
                (abbrev-mode 1)
                ;; This line is not in the documentation of snippet.el, but seems to be
                ;; essential for various modes (not for python-mode though, which serves as
                ;; the example mode in said documentation)
                (setq local-abbrev-table javascript-mode-abbrev-table)))

Download

You can find snippet.el at snippet.el

Small bug with Hippie Expand

This is great! However, I have a small problem: when trying to expand an underlined expression with hippie-expand, the text disapears. dabbrev-expand works fine though… Any idea ? – SebastienRoccaSerra

Yes, it’s really great! It behaves a bit funny wrt indentation, though. If I insert the snippet “{$>\n$>$.\n}$>” in a C mode buffer, the last brace is indented incorrectly. If I let the $. out of the snippet, it works as expected. Does anyone know why? – JonasOster


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