EXECUTE limits?

[landsman(at)mpb.gsfc.nasa.gov (Wayne Landsman)]

When IDL V5.0 was released, one of the new features was supposedly the removal
of language limits, e.g. "an unlimited number of variables is now accepted, and
users can freely add new variable names with the EXECUTE statement."

In practice, I find the V5.0 EXECUTE limits the same as they were in V4.0.

In the example below, I try to use EXECUTE to define an anonymous structure 
at run-time.    (Note that I can't use the CREATE_STRUCT function, because 
CREATE_STRUCT requires that one know the number of tags beforehand.)     This 
works fine so long as the EXECUTE string does not exceed a certain length -- 
which seems to vary from machine to machine.     Otherwise I get a "Program 
code area full" error message.

Note that I never have a problem if I instead write the structure definition 
string to a temporary procedure file and compile the file.   (This is the 
workaround used by Tom McGlynn's MRD_STRUCT procedure at 
http://idlastro.gsfc.nasa.gov/ftp/pro/structure)      So it does seem that 
problem is caused by (machine-dependent?) limits to the EXECUTE statement.

Any Comments?    

Wayne Landsman                              landsman@mpb.gsfc.nasa.gov

IDL> print,!VERSION
{ alpha OSF unix 5.1 Apr 13 1998}
IDL> a = 'd = {name:0'
IDL> for i=0,99 do a = a + ',name' + strtrim(i,2) + ':0'
IDL> a = a + '}'
IDL> res = execute(a)

d = {name:0,name0:0,name1:0,name2:0,name3:0,name4:0,name5:0,name6:0,name7:0,
name8:0,name9:0,name10:0,name11:0,name12:0,name13:0,name14:0,name15:0,name16:0,
name17:0,name18:0,name19:0,name20:0,name21:0,name22:0,name23:0,name24:0,
name25:0,name26:0,name27:0,name28:0,name29:0,name30:0,name31:0,name32:0,
name33:0,name34:0,name35:0,name36:0,name37:0,name38:0,name39:0,name40:0,
name41:0,name42:0,name43:0,name44:0,name45:0,name46:0,name47:0,name48:0,
name49:0,name50:0,name51:0,name52:0,name53:0,name54:0,name55:0,name56:0,
name57:0,name58:0,name59:0,name60:0,name61:0,name62:0,name63:0,name64:0,
name65:0,name66:0,name67:0,name68:0,name69:0,name70:0,name71:0,name72:0,
name73:0,name74:0,name75:0,name76:0,name77:0,name78:0,name79:0,name80:0,
name81:0,name82:0,name83:0,name84:0,name85:0,name86:0,name87:0,name88:0,
name89:0,name90:0,name91:0,name92:0,name93:0,name94:0,name95:0,name96:0,
name97:0,name98:0,name99:0}

% Program code area full.
       0