Inserting date command into snippet sublime text 3 - latex

Question

I am trying to create a snippet for starting a LaTex document where the packages and everything is filled in, but I also want it to automatically fill in the date. I have the insertdate package, but I did not understand how to use it. I have the snippet code:
<snippet>
<content><![CDATA[
\documentclass{article}
\usepackage{amsmath}
\title{${1:title}}
\author{...}
\date{[Todays date here automatically]}
\begin{document}
\maketitle
$0
\end{document}
]]></content>
<!-- Optional: Set a tabTrigger to define how to trigger the snippet -->
<tabTrigger>document</tabTrigger> -->
<!-- Optional: Set a scope to limit where the snippet will trigger -->
<scope>text.tex.latex</scope> -->
</snippet>

Answer 1

It's not directly possible to expand a snippet in the traditional way (i.e. documentTab in this case) and have one or more of the fields in the snippet dynamically update; for that you would need extra glue plugin code.
The InsertDate package provides a variety of ways to insert a date into your document, but that extra glue is not provided. An example of a way to do that is outlined below.
All of the examples below assume the following snippet content in a file named Packages/User/NewLatexDocument.sublime-snippet; in the following examples, replace that path with the appropriate path and file name of your snippet.
<snippet>
<content><![CDATA[
\documentclass{article}
\usepackage{amsmath}
\title{${2:title}}
\author{...}
\date{${1:date}}
\begin{document}
\maketitle
$0
\end{document}
]]></content>
<description>Create new LaTeX Document</description>
<tabTrigger>document</tabTrigger>
<scope>text.tex.latex</scope>
</snippet>
This is a version of the one you provided in your question, but note that the version in your question is broken because the <tabTrigger> and <scope> lines are terminated with the --> comment sequence, which is not valid.
Of particular interest here is that the snippet fields have been re-ordered so that the date field is the first one and the title is the second one, for reasons we'll see in a moment.
It's also important to know where your User package is; if you're not sure, you can find the location by selecting Preferences > Browse Packages... from the menu. On MacOS, the menu location is Sublime Text > Preferences > Browse Packages... instead.
Method 1: Expanding the snippet via the tab trigger (no extra plugin)
It's possible to invoke the snippet with the tab trigger (here the word document), but as mentioned above there's no direct way to get the InsertDate package to insert the date for you.
What you can do however is use one of the default key bindings to trigger a manual date insertion. An example of that would be pressing F5, which displays a panel of date options and then inserts one. From there you can press Tab to continue on in the snippet.
See the documentation for the package for all of the various keys that you can use here or to get a feel for how you could make your own custom binding to insert in the format of your choice directly.
This isn't directly what you want to do, but it's also the method that requires the least amount of work to set up.
Method 2: Expanding the snippet via a macro
By using a Sublime macro, you can take a single action (key press, command palette entry, etc) and have both actions happen automatically; expand the snippet and insert the date.
To do that, you would save the following contents into a sublime-macro in your User package. The name doesn't matter so long as you remember what you used because you're going to need it in a moment. In my examples below, the filename is Packages/User/NewLatexDocument.sublime-macro.
[
{ "command": "insert_snippet", "args": {"name": "Packages/User/NewLatexDocument.sublime-snippet"} },
{ "command": "insert_date", "args": {"format": "%x"} },
{ "command": "next_field" },
]
Make sure that the filename in the insert_snippet argument matches the name of your snippet. You probably also want to change the date format to whatever format you prefer.
When you invoke the macro, it inserts the snippet, then triggers the insert_date function to insert the date (this is why the date field is first) and skips to the next field, at which point you can start manually filling out the rest of the snippet.
You can see this in action by selecting Tools > Macros > User > NewLatexDocument from the menu; the final item will be the name of your sublime-macro file.
Now you can create a key binding that triggers the macro for you so you don't have to select it from the menu. As above, remember to ensure that the file name of the sublime-macro is the file you created.
{
"keys": ["ctrl+alt+shift+d"],
"command": "run_macro_file",
"args": {
"file": "res://Packages/User/NewLatexDocument.sublime-macro"
}
},
Alternatively, you can create a sublime-commands file in your User package (for example, MyCustomCommands.sublime-commands) with the following contents, which will make the command available in the Command Palette:
[
{
"caption": "Create new Latex Document",
"command": "run_macro_file",
"args": {
"file": "res://Packages/User/NewLatexDocument.sublime-macro"
}
},
]
Method 3: Expanding the snippet via the tab trigger (w/extra plugin)
This example is the closest to what you want to do but it requires a little bit more work. Additionally note that it requires you to enter the full expansion text (e.g. document) and won't trigger on a partial match if that happens to be the best completion.
To start with, make sure you've created the macro from Method 2, as this method uses that same macro but triggers it in a different way.
Next, select Tools > Developer > New Plugin... from the menu and replace the text of the default plugin with the following code, then save it as a .py file; in my example I named the file new_latex_document.py:
import sublime
import sublime_plugin
class NewLatexDocumentCommand(sublime_plugin.TextCommand):
def run(self, edit):
# Get the last word of the line the cursor is on
point = self.view.sel()[0].b
line = self.view.substr(self.view.line(point))
word = line.split()[-1]
# Remove the trigger word
self.view.replace(edit, sublime.Region(point, point - len(word)), "")
# Run the macro
self.view.run_command("run_macro_file", {
"file": "res://Packages/User/NewLatexDocument.sublime-macro"
})
This creates a command named new_latex_document (named based on the name of the class, not the name of the file you save the plugin in) which, when you invoke it, will erase the last word on the line where the cursor is sitting and then run the macro from method 2 above.
Now you need to add the following key binding to your custom keys:
{
"keys": ["tab"],
"command": "new_latex_document",
"context": [
{ "key": "selector", "operator": "equal", "operand": "text.tex.latex"},
{ "key": "preceding_text", "operator": "regex_match", "operand": "^.*document$", "match_all": true },
{ "key": "following_text", "operator": "regex_match", "operand": "^$", "match_all": true },
{ "key": "num_selections", "operator": "equal", "operand": 1},
{ "key": "selection_empty", "operator": "equal", "operand": "true", "match_all": true },
]
},
Broken down, this say that the Tab key should run our new command, but only in files of type text.tex.latex, where the text prior to the cursor location is the word document with no text following it, and when there is only a single cursor in the document with an empty selection.
Now when you enter the word document followed by Tab and these conditions are satisfied, the custom command runs, removing the trigger word document and then expanding the macro out to insert the snippet and the date.
Note that in this case, the tabTrigger and the scope in the sublime-snippet file are ignored, which is why the key binding needs to explicitly set them.
This plugin could be enhanced if desired; for example instead of running the run_macro_file command, it could just execute each of the commands from the macro directly, saving a step.
If you had many such expansions you wanted to do with a date, it's probably better to use an even more customized plugin; using an on_query_completions handler for example would allow the triggering to happen without requiring the key bindings.
That's a more advanced topic, however.