Passing arguments to mata functions

[li zhi]

why is there two arguments needed in the functions?What does touse stand for?I don't understand this paragraph in the help file about mata.Can anyone help me?

[William Lisowski]

I think you have found your way into an advanced part of the Mata documentation that you are not ready for. For better or worse, the documentation in each section of the Mata Reference Manual PDF is organized alphabetically by the name of the entries. The paragraph you quote comes from the entry for the advanced topic of using Mata with ado files.

In the manual, section M-0 contains a recommended reading list to learn Mata. You will be best served by reading the entries recommended there in the order given. I think perhaps you have attempted to read the manual in the order of the entries. This will be like trying to learn a language by reading the dictionary in alphabetical order.

Note that section M-0 also includes the following advice.

The Mata Reference Manual is comprehensive. If it seems overly comprehensive and too short on explanation as to why things work the way they do and how they could be used, we have a suggestion. See The Mata Book by William Gould (428 pages) or An Introduction to Stata Programming by Christopher Baum (412 pages). Baum's book assumes that you are familiar with Stata but new to programming. Gould's book assumes that you have some familiarity with programming and goes on from there. The books go well together.