Function precondition 

pub fn precondition<'a, MS: STeXModuleStore>(
    precondition: Macro<'a, LSPLineCol>,
    p: &mut LaTeXParser<'a, LSPLineCol, STeXToken<LSPLineCol>, STeXParseState<'a, LSPLineCol, MS>>,
) -> MacroResult<'a, LSPLineCol, STeXToken<LSPLineCol>>

Panics