Combining pure functions containing compound expressions
Background
For display purposes, I sometimes find it desirable to defeat Mathematica's canonical ordering of variables, and instead have it output terms in the order in which I type them. E.g., instead of this:
b-a
v=v0+a t
a8+a9+a10
–a + b
a t + v0
a10 + a8 + a9
...I'd prefer this:
b – a
v0 + a t
a8 + a9 + a10
This can be easily accomplished by removing the Orderless attributes from Plus and Times, entering the expression, and then immediately restoring those attributes (it is important to do the latter, since their absence alters basic functionality; e.g., without Orderless, Plus doesn't recognize that a + b is mathematically identical to b + a).
ClearAttributes[Plus, Orderless]
ClearAttributes[Times, Orderless]
c (b-a)
SetAttributes[Plus, Orderless]
SetAttributes[Times, Orderless]
c (b – a)
Question
How do I implement the above as a function? I.e., I'd like to define a function such that:
func[c (b-a)]
c (b-a) (*confirm that Orderless is restored to both Plus and Times*)
c (b – a)
(–a + b) c
Thus far I've only managed the following, which achieves the desired output, but requires I enter a function, then the expression, then another function:
func1 := (ClearAttributes[Plus, Orderless]; ClearAttributes[Times, Orderless]) &;
func2 := (SetAttributes[Plus, Orderless]; SetAttributes[Times, Orderless]) &;
func1[_]; c (b-a)
func2[_]
c (b-a)
c (b – a)
(–a + b) c
How do I combine these into a single function that takes the expression as its argument?
EDIT: Note that I want to alter only the display format, not any other functionality. E.g., MMA should still recognize that e1 and e2 are mathematically equivalent:
func1[_]
e1 = c (b - a)
e2 = (-a + b) c
func2[_]
e1 == e2
c (b - a)
(-a + b) c
True
output-formatting sorting output canonicalization
add a comment |
Background
For display purposes, I sometimes find it desirable to defeat Mathematica's canonical ordering of variables, and instead have it output terms in the order in which I type them. E.g., instead of this:
b-a
v=v0+a t
a8+a9+a10
–a + b
a t + v0
a10 + a8 + a9
...I'd prefer this:
b – a
v0 + a t
a8 + a9 + a10
This can be easily accomplished by removing the Orderless attributes from Plus and Times, entering the expression, and then immediately restoring those attributes (it is important to do the latter, since their absence alters basic functionality; e.g., without Orderless, Plus doesn't recognize that a + b is mathematically identical to b + a).
ClearAttributes[Plus, Orderless]
ClearAttributes[Times, Orderless]
c (b-a)
SetAttributes[Plus, Orderless]
SetAttributes[Times, Orderless]
c (b – a)
Question
How do I implement the above as a function? I.e., I'd like to define a function such that:
func[c (b-a)]
c (b-a) (*confirm that Orderless is restored to both Plus and Times*)
c (b – a)
(–a + b) c
Thus far I've only managed the following, which achieves the desired output, but requires I enter a function, then the expression, then another function:
func1 := (ClearAttributes[Plus, Orderless]; ClearAttributes[Times, Orderless]) &;
func2 := (SetAttributes[Plus, Orderless]; SetAttributes[Times, Orderless]) &;
func1[_]; c (b-a)
func2[_]
c (b-a)
c (b – a)
(–a + b) c
How do I combine these into a single function that takes the expression as its argument?
EDIT: Note that I want to alter only the display format, not any other functionality. E.g., MMA should still recognize that e1 and e2 are mathematically equivalent:
func1[_]
e1 = c (b - a)
e2 = (-a + b) c
func2[_]
e1 == e2
c (b - a)
(-a + b) c
True
output-formatting sorting output canonicalization
add a comment |
Background
For display purposes, I sometimes find it desirable to defeat Mathematica's canonical ordering of variables, and instead have it output terms in the order in which I type them. E.g., instead of this:
b-a
v=v0+a t
a8+a9+a10
–a + b
a t + v0
a10 + a8 + a9
...I'd prefer this:
b – a
v0 + a t
a8 + a9 + a10
This can be easily accomplished by removing the Orderless attributes from Plus and Times, entering the expression, and then immediately restoring those attributes (it is important to do the latter, since their absence alters basic functionality; e.g., without Orderless, Plus doesn't recognize that a + b is mathematically identical to b + a).
ClearAttributes[Plus, Orderless]
ClearAttributes[Times, Orderless]
c (b-a)
SetAttributes[Plus, Orderless]
SetAttributes[Times, Orderless]
c (b – a)
Question
How do I implement the above as a function? I.e., I'd like to define a function such that:
func[c (b-a)]
c (b-a) (*confirm that Orderless is restored to both Plus and Times*)
c (b – a)
(–a + b) c
Thus far I've only managed the following, which achieves the desired output, but requires I enter a function, then the expression, then another function:
func1 := (ClearAttributes[Plus, Orderless]; ClearAttributes[Times, Orderless]) &;
func2 := (SetAttributes[Plus, Orderless]; SetAttributes[Times, Orderless]) &;
func1[_]; c (b-a)
func2[_]
c (b-a)
c (b – a)
(–a + b) c
How do I combine these into a single function that takes the expression as its argument?
EDIT: Note that I want to alter only the display format, not any other functionality. E.g., MMA should still recognize that e1 and e2 are mathematically equivalent:
func1[_]
e1 = c (b - a)
e2 = (-a + b) c
func2[_]
e1 == e2
c (b - a)
(-a + b) c
True
output-formatting sorting output canonicalization
Background
For display purposes, I sometimes find it desirable to defeat Mathematica's canonical ordering of variables, and instead have it output terms in the order in which I type them. E.g., instead of this:
b-a
v=v0+a t
a8+a9+a10
–a + b
a t + v0
a10 + a8 + a9
...I'd prefer this:
b – a
v0 + a t
a8 + a9 + a10
This can be easily accomplished by removing the Orderless attributes from Plus and Times, entering the expression, and then immediately restoring those attributes (it is important to do the latter, since their absence alters basic functionality; e.g., without Orderless, Plus doesn't recognize that a + b is mathematically identical to b + a).
ClearAttributes[Plus, Orderless]
ClearAttributes[Times, Orderless]
c (b-a)
SetAttributes[Plus, Orderless]
SetAttributes[Times, Orderless]
c (b – a)
Question
How do I implement the above as a function? I.e., I'd like to define a function such that:
func[c (b-a)]
c (b-a) (*confirm that Orderless is restored to both Plus and Times*)
c (b – a)
(–a + b) c
Thus far I've only managed the following, which achieves the desired output, but requires I enter a function, then the expression, then another function:
func1 := (ClearAttributes[Plus, Orderless]; ClearAttributes[Times, Orderless]) &;
func2 := (SetAttributes[Plus, Orderless]; SetAttributes[Times, Orderless]) &;
func1[_]; c (b-a)
func2[_]
c (b-a)
c (b – a)
(–a + b) c
How do I combine these into a single function that takes the expression as its argument?
EDIT: Note that I want to alter only the display format, not any other functionality. E.g., MMA should still recognize that e1 and e2 are mathematically equivalent:
func1[_]
e1 = c (b - a)
e2 = (-a + b) c
func2[_]
e1 == e2
c (b - a)
(-a + b) c
True
output-formatting sorting output canonicalization
output-formatting sorting output canonicalization
edited 2 hours ago
asked 5 hours ago
theorist
1,077420
1,077420
add a comment |
add a comment |
1 Answer
1
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oldest
votes
You could define a format that does this for you:
SetAttributes[orderlessForm, HoldFirst]
MakeBoxes[orderlessForm[expr_], form_] ^:= Internal`InheritedBlock[{Times, Plus},
ClearAttributes[{Times, Plus}, Orderless];
MakeBoxes[expr, form]
]
Then:
orderlessForm[c (b - a)]
c (b - a)
And, the usual output when not using the wrapper:
c (b - a)
(-a + b) c
Note that the HoldFirst
attribute does most of the work.
Thanks Carl. One problem I notice is that orderlessForm alters some functionality. E.g.,e1 = orderlessForm[a + b];
e2 = orderlessForm[b + a];
e1 == e2
givesa + b == b + a
instead ofTrue
. I've added an edit at the end of my question to make this requirement explicit.
– theorist
2 hours ago
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You could define a format that does this for you:
SetAttributes[orderlessForm, HoldFirst]
MakeBoxes[orderlessForm[expr_], form_] ^:= Internal`InheritedBlock[{Times, Plus},
ClearAttributes[{Times, Plus}, Orderless];
MakeBoxes[expr, form]
]
Then:
orderlessForm[c (b - a)]
c (b - a)
And, the usual output when not using the wrapper:
c (b - a)
(-a + b) c
Note that the HoldFirst
attribute does most of the work.
Thanks Carl. One problem I notice is that orderlessForm alters some functionality. E.g.,e1 = orderlessForm[a + b];
e2 = orderlessForm[b + a];
e1 == e2
givesa + b == b + a
instead ofTrue
. I've added an edit at the end of my question to make this requirement explicit.
– theorist
2 hours ago
add a comment |
You could define a format that does this for you:
SetAttributes[orderlessForm, HoldFirst]
MakeBoxes[orderlessForm[expr_], form_] ^:= Internal`InheritedBlock[{Times, Plus},
ClearAttributes[{Times, Plus}, Orderless];
MakeBoxes[expr, form]
]
Then:
orderlessForm[c (b - a)]
c (b - a)
And, the usual output when not using the wrapper:
c (b - a)
(-a + b) c
Note that the HoldFirst
attribute does most of the work.
Thanks Carl. One problem I notice is that orderlessForm alters some functionality. E.g.,e1 = orderlessForm[a + b];
e2 = orderlessForm[b + a];
e1 == e2
givesa + b == b + a
instead ofTrue
. I've added an edit at the end of my question to make this requirement explicit.
– theorist
2 hours ago
add a comment |
You could define a format that does this for you:
SetAttributes[orderlessForm, HoldFirst]
MakeBoxes[orderlessForm[expr_], form_] ^:= Internal`InheritedBlock[{Times, Plus},
ClearAttributes[{Times, Plus}, Orderless];
MakeBoxes[expr, form]
]
Then:
orderlessForm[c (b - a)]
c (b - a)
And, the usual output when not using the wrapper:
c (b - a)
(-a + b) c
Note that the HoldFirst
attribute does most of the work.
You could define a format that does this for you:
SetAttributes[orderlessForm, HoldFirst]
MakeBoxes[orderlessForm[expr_], form_] ^:= Internal`InheritedBlock[{Times, Plus},
ClearAttributes[{Times, Plus}, Orderless];
MakeBoxes[expr, form]
]
Then:
orderlessForm[c (b - a)]
c (b - a)
And, the usual output when not using the wrapper:
c (b - a)
(-a + b) c
Note that the HoldFirst
attribute does most of the work.
answered 3 hours ago
Carl Woll
67k387175
67k387175
Thanks Carl. One problem I notice is that orderlessForm alters some functionality. E.g.,e1 = orderlessForm[a + b];
e2 = orderlessForm[b + a];
e1 == e2
givesa + b == b + a
instead ofTrue
. I've added an edit at the end of my question to make this requirement explicit.
– theorist
2 hours ago
add a comment |
Thanks Carl. One problem I notice is that orderlessForm alters some functionality. E.g.,e1 = orderlessForm[a + b];
e2 = orderlessForm[b + a];
e1 == e2
givesa + b == b + a
instead ofTrue
. I've added an edit at the end of my question to make this requirement explicit.
– theorist
2 hours ago
Thanks Carl. One problem I notice is that orderlessForm alters some functionality. E.g.,
e1 = orderlessForm[a + b];
e2 = orderlessForm[b + a];
e1 == e2
gives a + b == b + a
instead of True
. I've added an edit at the end of my question to make this requirement explicit.– theorist
2 hours ago
Thanks Carl. One problem I notice is that orderlessForm alters some functionality. E.g.,
e1 = orderlessForm[a + b];
e2 = orderlessForm[b + a];
e1 == e2
gives a + b == b + a
instead of True
. I've added an edit at the end of my question to make this requirement explicit.– theorist
2 hours ago
add a comment |
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