Pref::alias -- controls the output
of aliased expressions
IntroductionPref::alias(TRUE) switches the usage of
alias abbrevations in
outputs on.
Pref::alias(FALSE) switches the usage of
alias abbrevations in
outputs off.
Pref::alias() returns the current
setting.
Call(s)Pref::alias()
Pref::alias(TRUE)
Pref::alias(FALSE)
Pref::alias(NIL)
Returnsthe last defined value
Side
EffectsPref::alias changes the output of aliased
expressions.
Related
Functionsalias, expr2text, fprint, print
Detailsalias is an
abbrevation for a MuPAD expression. If Pref::alias
is enabled, the alias abbrevations will be used for
output.Pref::alias() returns the current
value.Pref::alias(TRUE) switches the usage of
alias abbrevations in
outputs on. This is the default setting.Pref::alias(FALSE) switches the usage of
aliases in outputs off.Pref::alias(NIL) restores the default
value which is TRUE.Pref::alias has no effect on print and fprint.
Example
1If an aliased expression occurs in output, it is replaced by the alias abbrevation:
>> alias(X = a + b): X, a + b
X, X
This only works if the syntactical structure of expression matches the aliased expression:
>> 2*X
2 a + 2 b
prog::exprtree shows that
2*X does not contain a + b any more:
>> prog::exprtree(X): prog::exprtree(2*X):
_plus
|
+-- a
|
`-- b
_plus
|
+-- _mult
| |
| +-- a
| |
| `-- 2
|
`-- _mult
|
+-- b
|
`-- 2
The same holds for X+c:
>> X + c; prog::exprtree(X + c):
a + b + c
_plus
|
+-- a
|
+-- b
|
`-- c
With Pref::alias(FALSE) the
back translation of aliases in the output is disabled:
>> Pref::alias(FALSE): X
a + b
Pref::alias has no effect on print and fprint outputs:
>> Pref::alias(TRUE): print(X):
a + b