vscode new language configuration not changing syntax colors - json

Question

I'm trying to create a new language for syntax highighting in Visual Studio Code for the CPU12 assembly language. When I use the new language in a new .asm file, the editor knows that the comment character is (it adds a semicolon to a line when I type ctrl-k ctrl-c), but the text is white instead of the default comment color green. Do I need to specify to use the default vscode theme? If so, where?
package.json
{
"name": "cpu12",
"displayName": "cpu12",
"description": "cpu12",
"version": "0.0.1",
"publisher": "https://github.com/me",
"engines": {
"vscode": "^1.15.0"
},
"categories": [
"Languages"
],
"contributes": {
"languages": [{
"id": "cpu12",
"aliases": ["CPU12", "cpu12"],
"extensions": [".asm",".inc"],
"configuration": "./language-configuration.json"
}],
"grammars": [{
"language": "cpu12",
"scopeName": "source.cpu12",
"path": "./syntaxes/cpu12.tmLanguage.json"
}]
}
}
language-configuration.json
{
"comments": {
// symbol used for single line comment. Remove this entry if your language does not support line comments
"lineComment": ";"
},
// symbols used as brackets
"brackets": [
["{", "}"],
["[", "]"],
["(", ")"]
],
// symbols that are auto closed when typing
"autoClosingPairs": [
["{", "}"],
["[", "]"],
["(", ")"],
["\"", "\""],
["'", "'"]
],
// symbols that that can be used to surround a selection
"surroundingPairs": [
["{", "}"],
["[", "]"],
["(", ")"],
["\"", "\""],
["'", "'"]
]
}
(My ./syntaxes/cpu12.tmLanguage.json is empty.)

Answer 1

The problem was actually because ./syntaxes/cpu12.tmLanguage.json was empty. You need to specify in the .json file how to color line comments:
./syntaxes/cpu12.tmLanguage.json
{
"$schema": "https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json",
"name": "cpu12",
"scopeName": "source.cpu12",
"patterns": [
{
"comment": "Line Comments -- Asterisk only works at beginning of line",
"match": "((;|^\\*).*$)",
"captures": {
"1" :{
"name": "comment.line.cpu12"
}
}
}
]
}