How to avoid auto-close (, {, [ in user defined Sublime Text 3 snippet? - autocomplete

Question

I'm trying to write a fairly innocent-looking snippet fro ST3. For inserting
\left<open-parens> \right<close-parens>
into a latex document while in a math scope.
What I have now, is this:
<snippet>
<content><![CDATA[\\left${1:(} $0 \\right${1/(\()|(\{)|(\[)/(?1:\))(?2:\})(?3:\])/}]]></content>
<tabTrigger>lft</tabTrigger>
<scope>text.tex.latex string.other.math.tex,meta.function.environment.math.latex</scope>
</snippet>
The usage is intended as follows:
Type lst,tab;
\left( \right) is inserted with the ( selected;
If user wants (, tab to land in in middle;
Else type { or [ to have corresponding closing parens inserted after \right
I have verified that the regex is working as intended (by trying out versions of the snippet with ${1:(} replaced by ${1:{} and ${1:[}.
However in usage, when typing any start parens, ST calls it's own snippet, a) inserting the close parens immediately after and b) removing focus from my snippet, so the the regex is never called.
The first problem, I have been able to alleviate, by capturing the opening parenses and call a tiny snippet, inserting the character itself. E.g:
{ "keys": ["{"], "command": "insert_snippet", "args": {"contents": "$0{"}, "context": [
{"key": "selector", "operator": "equal", "operand": "text.tex.latex string.other.math.tex, meta.function.environment.math.latex"},
{"key": "preceding_text", "operator": "regex_contains", "operand": "\\\\left\\($", "match_all": true }] },
But then I discovered b).
A solution would involve either of:
Prevent execution of built-in auto-close snippets, depending on context and "key": "preceding_text".
Making my own mini-snippet return to the former (i.e. after typing [focus returns to the lst-snippet).
How can this be achieved?

Answer 1

This isn't really the answer I'm looking for, but rather a working solution to this specific issue.
The use becomes a little different in looks but the keystrokes required are the same.
What I do is this:
Change the lft-snippet to:
<content><![CDATA[\\left${1:$0\right}]]></content>
For each parens-type define a new keybinding, that overrides the default and does something useful, e.g. for the [] add this to a keymap file:
{ "keys": ["["], "command": "insert_snippet", "args": {"contents": "[ $0 $SELECTION]"}, "context":
[
{ "key": "setting.auto_match_enabled", "operator": "equal", "operand": true },
{ "key": "selection_empty", "operator": "equal", "operand": false, "match_all": true },
{ "key": "selector", "operator": "equal", "operand": "text.tex.latex string.other.math.tex, meta.function.environment.math.latex"},
{ "key": "preceding_text", "operator": "regex_contains", "operand": "\\\\left\\\\right$", "match_all": true }
]
},
As a positive side effect the lft-snippet becomes a lot easier to read (removing the regex).
I would still very much like to know of ways to accomplish this in a more general way.