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Why do I get syntax errors when I use local macros in my do-file?

Title   Dealing with syntax errors when using local macros
Author Kerry Kammire, StataCorp

These types of errors will appear when you use macros in a do-file and try to run a selection of your do-file.

This behavior occurs because the Do-file Editor turns the line or lines you select in a do-file into a new temporary do-file and runs it separately from the original do-file. The local macros you defined in the original do-file are not defined in the new smaller temporary do-file that is created. This makes all the local macros become blank macros, and they are expanded into an empty spot in the command, which generally triggers a syntax error.

For example, say we have a do-file that contains the following lines:

local keyvar mylongvariablename
generate `keyvar' = hours/2
replace x = `keyvar'*5

When we run it all together, it works fine, but if we select the generate or replace lines and run them by themselves, we will get:

. generate `keyvar' = hours/2
too few variables specified
r(102);
and
. replace x = `keyvar'*5
*5 invalid name
r(198);

The local macro `keyvar' will be empty so Stata will see those commands as if we ran incomplete commands like:

generate  = hours/2

replace x = *5

There are two common ways to resolve this issue. The first is defining the macro in the part you are selecting, so it will be present when you run the selection, such as running all three lines in the first example code.

The other method is for when the macro is defined in another section of the do-file, and the commands are not adjacent to it. In that case, you can use the "/* */" comments to block out the parts you want to skip and run the whole do-file, or you can make sure that the block you highlight includes the local macro so that it can be recognized for the rest of the computations:

local keyvar mylongvariablename

/*
summarize mpg
regress price rep78 foreign
scatter weight mpg
*/

generate `keyvar' = hours/2
replace x = `keyvar'*5