Re: [NTGcontext] metafun: error when I call the same function twice consecutively.
Dear Henri Menke, Thank you for the solution. After inserting a line “save x, y;”, it works. Thank you so much. Best regards, Dalyoung
On Fri, 01 Jun 2018 20:29:41 +0900
Jeong Dal
After inserting a line “save x, y;”, it works.
This is also defined as "clearxy ;" For those learning MetaPost, simplifying, z is defined as "(x,y)" so one can write z = (a,b) ; This is an EQUATION in MetaPost (x,y) = (a,b) ; not an assignment (as in most other languages), actually a pair of equations: x = a ; y = b ; When x and y are unknown, this can be "solved". When x and y contain values, it leads to "inconsistent equations". One *cannot* write z =: (a,b) ; ("=:" is the assignment operator), for z is just a macro, not a "pair" object or variable. This can be *very* confusing when learning MetaPost. Alan P.S. for i=0 upto n: z[i] = (i,0) ; endfor works as each element of the (pseudo)array z is unknown, at least the first time that it is used.
Dear Alan, Thank you for the clear explanation about z. I tought that z is a special variable different from other pairs. Now, I know that it is an equation. Thank you again. Best regards, Dalyoung
2018. 6. 1. 오후 11:24, Alan Braslau
작성: On Fri, 01 Jun 2018 20:29:41 +0900 Jeong Dal
wrote: After inserting a line “save x, y;”, it works.
This is also defined as "clearxy ;"
For those learning MetaPost, simplifying, z is defined as "(x,y)" so one can write z = (a,b) ; This is an EQUATION in MetaPost (x,y) = (a,b) ; not an assignment (as in most other languages), actually a pair of equations: x = a ; y = b ; When x and y are unknown, this can be "solved". When x and y contain values, it leads to "inconsistent equations".
One *cannot* write z =: (a,b) ; ("=:" is the assignment operator), for z is just a macro, not a "pair" object or variable.
This can be *very* confusing when learning MetaPost.
Alan
P.S. for i=0 upto n: z[i] = (i,0) ; endfor works as each element of the (pseudo)array z is unknown, at least the first time that it is used.
participants (2)

Alan Braslau

Jeong Dal