mf_st_macroexpand.hlp

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{smcl}
{* 07may2005}{...}
{cmd:help mata st_macroexpand()}
{hline}
{* index st_macroexpand()}{...}
{* index _st_macroexpand()}{...}

{title:Title}

{p 4 4 2}
{bf:[M-5] st_macroexpand() -- Expand Stata macros in string}


{title:Syntax}

{p 8 12 2}
{it:string scalar}
{cmd:st_macroexpand(}{it:string scalar s}{cmd:)}

{p 8 12 2}
{it:real scalar}{bind: }
{cmd:_st_macroexpand(}{it:S}{cmd:,} 
{it:string scalar s}{cmd:)}


{p 4 11 2}
Note:
The type of {it:S} does not matter; it is replaced and becomes a 
string scalar.


{title:Description}

{p 4 4 2}
{cmd:st_macroexpand(}{it:s}{cmd:)}
returns {it:s} with any quoted or dollar-sign prefixed macros expanded.

{p 4 4 2}
{cmd:_st_macroexpand(}{it:S}{cmd:,} {it:s}{cmd:)}
places in {it:S} the contents of {it:s} with any quoted or dollar-sign 
prefixed macros expanded, and returns a Stata return code (it returns 
0 if all went well).


{title:Remarks}

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Be careful coding string literals containing quoted or prefixed macros
because macros are also expanded at compile time.  For instance,
consider 

	{cmd:s = st_macroexpand("regress `varlist'")}

{p 4 4 2}
{cmd:`varlist'} will be substituted with its value at compile time.  What you
probably want is

        {cmd:s = st_macroexpand("regress " + "`" + "varlist" + "'")}


{title:Conformability}

    {cmd:st_macroexpand(}{it:s}{cmd:)}:
		{it:s}:  1 {it:x} 1
	   {it:result}:  1 {it:x} 1

    {cmd:_st_macroexpand(}{it:S}{cmd:,} {it:s}{cmd:)}:
	{it:input:}
		{it:s}:  1 {it:x} 1
	{it:output:}
		{it:S}:  1 {it:x} 1
	   {it:result}:  1 {it:x} 1


{title:Diagnostics}

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{cmd:st_macroexpand(}{it:s}{cmd:)} aborts with error if {it:s} is too long
(exceedingly unlikely) or if macro expansion fails (also unlikely).

{p 4 4 2}
{cmd:_st_macroexpand(}{it:S}{cmd:,} {it:s}{cmd:)} aborts with error if {it:s}
is too long.  


{title:Source code}

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Functions are built-in.


{title:Also see}

{p 4 13 2}
Manual:  {hi:[M-5] st_macroexpand()}

{p 4 13 2}
Online:  help for 
{bf:{help m4_stata:[M-4] stata}}
{p_end}