In Lua, the entire Match-IT extension is available through a module called 'match_it'. To access this module, all scripts and PPS expressions must include the line:
m = require('match_it') --load Match-IT into 'm'
This creates a table (called 'm' in the example above) where all functions, constants, etc. are presented as keys in the table. Unless shown otherwise all names mentioned in this document must be prefixed by the table name using the usual dot notation, e.g. m.open(mch).
Lua is a case sensitive language, whereas Match-IT is not. Keys in the Match-IT table are added on demand the first time you use them. When keys are added they are added using whatever case convention you used. If you are not consistent on case usage, it just results in multiple table entries, one for each case convention. This is benign but wasteful.