The things checked are:
Mismatched groups (braces), environments and math mode delimiters. When a mismatch is found, line numbers for both start and end of the mismatch is given. The error messages comes in pairs, one for the end match and one for the beginning, marked with `<-' and `->' respectively.
Bad spacing including missing a `\ ' after an abbreviation, missing an `\@' before a punctuation mark in a paragraph that is ended by an capital letter, double spaces like ` ~', bad usage of ellipsis (like using ... instead of \ldots, or using \ldots where \cdots should be used), missing ~ before a \cite or \ref commands, space before footnotes, italic corrections before comma, point, or italic text, italic correction after normal text, missing italic correction when switching from italic to normal text, and double italic correction.
Badly placed punctuation marks around end of math mode delimiters. This is, punctuation placed right after display math end or punctuation placed right before text math end. Sequences of whitespace followed by punctuation marks are also caught.
Bad use of quotation characters, i.e. constructs like "'word" or "word`" are warned about, tabs in verbatim environments are caught, certain TeX primitives are frowned upon, attempts to give font specifiers arguments such as \em{text} are noted, and use of @ in LaTeX macros are reported.
LaCheck will read files that are input using \input or \include. Files with suffix `.sty' are omitted, as they probably will cause LaCheck to crash.
LaCheck may be invoked from within Emacs(1) using compile: To run: M-x compile RET lacheck RET , and then C-x ` to parse the messages
A control space `\ ' should be inserted at line 34, to prevent an end-of-sentence space. Also, at line 179, the first space of the sequence " ~" should probably be deleted. The last two lines is an example, where the user mistyped, and probably inserted an extra "}" somewhere.
A mismatch error may cause more to follow, due to the chosen algorithm. In such cases just correct the first error and run LaCheck again
Braces, environments and math mode must be balanced within a file.
LaCheck may be confused by unmatched stuff placed inside verbatim-like environments called something else than exactly `verbatim'.
Ideas for improvements and bug reports are very welcome. Such should be directed to the maintainers, their email address is <auc-tex_mgr@sunsite.auc.dk>.