Support TypeScript

Like it says. I’m not sure how much of an effort this would be.

Known bugs/missing features

• Old-style casting (<Foo> bar). This conflicts with JSX, so I’ll have to make sure that this is configurable. Implemented in beta.3
• Type arguments in method calls. On the surface, this is ambiguous with ordinary JS syntax. I’ll have to look into exactly how TypeScript parses this. May require branching.
• Type arguments in template strings. Same concerns as above. May also require a special case for Styled Components.
• Better detection of arrow function argument lists. May require branching.
• Arrow function type parameters. Almost certainly require branching.
• Directives in comments. For this, I’ll need to figure out a general system for extending comments that works for other extensions as well.

[Thom1729]

I’m closing this because the beta release should fix everything in the initial psot.

[Thom1729]

Fun fact: in order to support function call type arguments, Microsoft’s official TypeScript syntax uses the following regular expressions:

(?=(((([_$[:alpha:]][_$[:alnum:]]*)(\s*\??\.\s*(\#?[_$[:alpha:]][_$[:alnum:]]*))*)|(\??\.\s*\#?[_$[:alpha:]][_$[:alnum:]]*))|(?<=[\)]))\s*(?:(\?\.\s*)|(\!))?((<\s*(((keyof|infer|awaited|typeof|readonly)\s+)|(([_$[:alpha:]][_$[:alnum:]]*|(\{([^\{\}]|(\{[^\{\}]*\}))*\})|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(\[([^\[\]]|(\[[^\[\]]*\]))*\])|(\'([^\'\\]|\\.)*\')|(\"([^\"\\]|\\.)*\")|(\`([^\`\\]|\\.)*\`))(?=\s*([\<\>\,\.\[]|=>|&(?!&)|\|(?!\|)))))([^<>\(]|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(?<==)\>|\<\s*(((keyof|infer|awaited|typeof|readonly)\s+)|(([_$[:alpha:]][_$[:alnum:]]*|(\{([^\{\}]|(\{[^\{\}]*\}))*\})|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(\[([^\[\]]|(\[[^\[\]]*\]))*\])|(\'([^\'\\]|\\.)*\')|(\"([^\"\\]|\\.)*\")|(\`([^\`\\]|\\.)*\`))(?=\s*([\<\>\,\.\[]|=>|&(?!&)|\|(?!\|)))))(([^<>\(]|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(?<==)\>|\<\s*(((keyof|infer|awaited|typeof|readonly)\s+)|(([_$[:alpha:]][_$[:alnum:]]*|(\{([^\{\}]|(\{[^\{\}]*\}))*\})|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(\[([^\[\]]|(\[[^\[\]]*\]))*\])|(\'([^\'\\]|\\.)*\')|(\"([^\"\\]|\\.)*\")|(\`([^\`\\]|\\.)*\`))(?=\s*([\<\>\,\.\[]|=>|&(?!&)|\|(?!\|)))))([^<>\(]|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(?<==)\>)*(?<!=)\>))*(?<!=)\>)*(?<!=)>\s*)?\())

(?<=\))(?!(((([_$[:alpha:]][_$[:alnum:]]*)(\s*\??\.\s*(\#?[_$[:alpha:]][_$[:alnum:]]*))*)|(\??\.\s*\#?[_$[:alpha:]][_$[:alnum:]]*))|(?<=[\)]))\s*(?:(\?\.\s*)|(\!))?((<\s*(((keyof|infer|awaited|typeof|readonly)\s+)|(([_$[:alpha:]][_$[:alnum:]]*|(\{([^\{\}]|(\{[^\{\}]*\}))*\})|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(\[([^\[\]]|(\[[^\[\]]*\]))*\])|(\'([^\'\\]|\\.)*\')|(\"([^\"\\]|\\.)*\")|(\`([^\`\\]|\\.)*\`))(?=\s*([\<\>\,\.\[]|=>|&(?!&)|\|(?!\|)))))([^<>\(]|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(?<==)\>|\<\s*(((keyof|infer|awaited|typeof|readonly)\s+)|(([_$[:alpha:]][_$[:alnum:]]*|(\{([^\{\}]|(\{[^\{\}]*\}))*\})|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(\[([^\[\]]|(\[[^\[\]]*\]))*\])|(\'([^\'\\]|\\.)*\')|(\"([^\"\\]|\\.)*\")|(\`([^\`\\]|\\.)*\`))(?=\s*([\<\>\,\.\[]|=>|&(?!&)|\|(?!\|)))))(([^<>\(]|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(?<==)\>|\<\s*(((keyof|infer|awaited|typeof|readonly)\s+)|(([_$[:alpha:]][_$[:alnum:]]*|(\{([^\{\}]|(\{[^\{\}]*\}))*\})|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(\[([^\[\]]|(\[[^\[\]]*\]))*\])|(\'([^\'\\]|\\.)*\')|(\"([^\"\\]|\\.)*\")|(\`([^\`\\]|\\.)*\`))(?=\s*([\<\>\,\.\[]|=>|&(?!&)|\|(?!\|)))))([^<>\(]|(\(([^\(\)]|(\([^\(\)]*\)))*\))|(?<==)\>)*(?<!=)\>))*(?<!=)\>)*(?<!=)>\s*)?\())

I was going to borrow Microsoft’s lookaheads as a temporary measure before reimplementing with branching, but upon reflection, I think not.