File Dependent Key Bindings - keyboard-shortcuts

Question

I have added following piece of code to Preferences > Key Bindings - User configruation file in my Sublime Text 3:
{ "keys": ["ctrl+b"], "command": "insert_snippet", "args": {"contents": "<strong>${0:$SELECTION}</strong>"} },
As a result, when user presses Ctrl+B in editor, current selection is surrounded with HTML tags <strong> and <strong>.
Is there anyway, I can make this setting file-type depended? I.e. if user is working in *.txt or *.md file, then pressing Ctrl+B in editor should surround selection with Markdown bold tag (**) and, when editing any other type of file (in general or *.html files in particular), then to surround with HTML tags, as in above example.
Is this possible in Sublime Text 3?

Answer 1

This can be done with the context parameter:
"context": [
{
"key": "selector",
"operator": "equal",
"operand": "source.php"
}
]
selector Returns the name of the current scope.
operator Type of test to perform against key‘s value. Defaults to equal.
operand The result returned by key is tested against this value.
More help see: http://docs.sublimetext.info/en/latest/reference/key_bindings.html
Examples
For recognizing Ctrl+B in HTML only
// bold snippet for html
{
"keys": ["ctrl+b"],
"command": "insert_snippet",
"args": {"contents": "<strong>${0:$SELECTION}</strong>"},
"context": [
{"key": "selector", "operator": "equal", "operand": "text.html.basic"}
]
},
For recognizing Ctrl+B in Markdown and plain text:
// bold snippet for markdown and plain text
{
"keys": ["ctrl+b"],
"command": "insert_snippet",
"args": {"contents": "**${0:$SELECTION}**"},
"context": [
{"key": "selector", "operator": "equal", "operand": "(text.html.markdown, text.plain)"}
]
},