st: saving to locals in Mata

[Kit Baum <baum@bc.edu>]

sacrificial lamb

Julian said

I am having trouble saving to locals using Mata. The following ADO  
code demonstrates my problem:

***example.ado code***

	program example
		version 9.2

		mata: example()
	end

	mata:
		void example()
		{
			t = "string"
			st_local("my_local",t)
			stata(`" di "my_local is `my_local'""')
		}	
	end

***end example.ado code***


No problem if instead you include the line

  di "the local is `my_local'"

in the Stata program. It might be that the stata() function is  
executed in a different context than that of the calling program (in  
which my_local is local). For instance,

	program example
		version 9.2

	local test test
		mata: example()
		di "the local is `my_local'"
		
	end

	mata:
		void example()
		{
			t = "string"
			st_local("my_local",t)
			stata(`" di "my_local is `my_local'""')
			stata(`" di "test is `test'""')
		}	
	end

does not display the value of test within Mata, either, although it  
is certainly defined in program example. But then why not just work  
with my_local back in the Stata program, anyway?



Kit Baum, Boston College Economics and DIW Berlin
http://ideas.repec.org/e/pba1.html
An Introduction to Modern Econometrics Using Stata:
http://www.stata-press.com/books/imeus.html


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