isglobal
checks if a local variable has a global counterpart
Syntax
t = isglobal(varname)
Arguments
- varname
text: name of any single local variable. This is not the variable itself (that provides its content), but its name.
- t
a boolean
Description
isglobal("x") returns %T if the variable
x is defined locally and points to a global counterpart. It returns
%F otherwise.
 |
|
 | The list of all variables defined in the global space (but not necessarily in the local
one) can be retrieved with who("global"). |
Examples
Example #1 with a predefined global variable:
mprintf("%s\n", who("global")) // demolist has a global definition... isdef("demolist") // %F: ... but no local one (not yet) demolist(1) // => "Undefined variable" isglobal("demolist") // => %F, since it has no local definition global demolist // We define a local demolist and make it pointing to the existing global one demolist($,:) // Here is the last row of the existing global content isglobal("demolist") // => now %T
--> mprintf("%s\n", who("global")) // demolist has a global definition...
%helps
%modalWarning
%toolboxes
%toolboxes_dir
demolist
--> isdef("demolist") // ... but no local one (not yet)
ans =
F
--> demolist(1) // So: => "Undefined variable"
Undefined variable: demolist
--> isglobal("demolist") // => %F, since it has no local definition
ans =
F
--> global demolist // We define a local demolist and make it pointing to the existing global one
--> demolist($,:) // Here is the last row of the existing global content
ans =
!Xcos SCI\modules\xcos\demos\xcos.dem.gateway.sce !
--> isglobal("demolist") // => now %T
ans =
T
Example #2 with a custom variable:
// In the list hereabove, "abc" does not exist. Let's create it locally and globally: global abc // initialized with [] isdef("abc") // => %T isglobal("abc") // => %T abc = %pi; // Writes simultaneously in the local AND global spaces clear abc // We delete the local definition, but not the global one abc // => "undefined variable" isglobal("abc") // => %F, since there is no longer any local alias global abc // We redefine abc connected to its global counterpart. What is it? abc
--> // In the list hereabove, "abc" does not exist. Let's create it locally and globally:
--> global abc // initialized with []
--> isdef("abc")
ans =
T
--> isglobal("abc")
ans =
T
--> abc = %pi; // Writes simultaneously in the local AND global spaces
--> clear abc // We delete the local definition, but not the global one
--> abc // => "undefined variable"
Undefined variable: abc
--> isglobal("abc") // => %F, since without local alias
ans =
F
--> global abc // We redefine abc connected to its global counterpart. What is it?
--> abc
abc =
3.1415927
See also
- global — define variável global
- clearglobal — cancela variáveis globais
- who — listagem de variáveis
- isdef — verifica existência de variáveis
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