libraries

[Wink Saville]

I am thinking about the future and I can see myself creating many libraries. I'm starting on lib-airfoil.curv and one of the functions I've created is "normailize".  I can imagine I might create different library in the future that also has a "normalize" function.

How can I use two different libraries that might have conflicting names?

An example, currently I can do something like this:

$ cat -n x.curv
     1 do
     2  // Load the library
     3  local include file "lib-airfoil.curv";
     4
     5  // Define an array of x,y points that is the airfoil section
     6  local af = [[4, 0], [1 ,1], [0, 0], [1, 0]];
     7
     8  // call the normalize function in lib-airfoil.curv and set nAf.
     9  local nAf = normalize(af);
    10 in
    11  polygon nAf >> scale 10
    12

But I'd like to do something like below, where I include lib-airfoil.curv

and assign it to a "local" name, "laf". Then use record syntax to execute

"local nAf = laf.normalize(af)":

$ cat -n y.curv
     1 do
     2  // Load the library
     3  local laf = include file "lib-airfoil.curv";
     4
     5  // Define an array of x,y points that is the airfoil section
     6  local af = [[4, 0], [1 ,1], [0, 0], [1, 0]];
     7  
     8  // call the laf.normalize function in lib-airfoil.curv and set nAf.
     9  local nAf = laf.normalize(af);
    10 in
    11  polygon nAf >> scale 10
    12

Of course the syntax doesn't work:

curv -l y.curv
ERROR: syntax error
at file "y.curv":
3|   local laf = include file "lib-airfoil.curv";
                 ^^^^^^^                        

So is there a syntax that can solve the problem?

[Alexandre François Garreau]

Le jeudi 18 juin 2020, 06:49:10 CEST Wink Saville a écrit :
> curv -l y.curv
> ERROR: syntax error
> at file "y.curv":
> 3| local laf = include file "lib-airfoil.curv";
> ^^^^^^^
>
> So is there a syntax that can solve the problem?

I’m rusty but aren’t you meant to remove “include” and let only “file” when
assigning it? Afair curv libraries work exactly like that: they’re
records that are loaded into variables and then accessed by dotted
notation.

I also note that syntax error seems not verbose enough to describe the
problem (only stating there is one), or am I wrong?

[Doug Moen]

Alexandre is correct.

'file "lib-airfoil.curv"' is an expression that returns a record value.
Try it in the REPL:
curv> file "lib-airfoil.curv"

'include <record-expression>' is definition syntax that defines a variable for each field in a record value.
Similar to "from module import *" in Python, if you know Python.
Try it in the REPL:
curv> include {a:1,b:2}
curv> a
1
curv> b
2

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[Wink Saville]

Simply removing "include" from line 3 and worked on my "y.curv" file:

$ cat -n y.curv

     1 do

     2   // Load the library

     3   local laf = file "lib-airfoil.curv";

     4

     5   // Define an array of x,y points that is the airfoil section

     6   local af = [[4, 0], [1 ,1], [0, 0], [1, 0]];

     7   

     8   // call the laf.normalize function in lib-airfoil.curv and set nAf.

     9   local nAf = laf.normalize(af);

    10 in

    11   polygon nAf >> scale 10

    12

THANKS, to both of you!