"Bill Page" <[EMAIL PROTECTED]> writes: | panAxiom developers, | | I just wanted to mention something here that I just learned about how | the Axiom interpreter handles option arguments. When discovering how | the 'draw' operations in Axiom processes optional arguments, e.g. | | draw(sin(x), x=1..10, title=="sin function")
Hmm, I thought I already mentioned this in discussions with Ralf ;-/ | | I realized the interpreter does something rather clever but probably | quite unexpected. It is the post parser doing it. And I don't like it -- the irony is that I made Boot do the same. | The problem is that (unlike Aldor) SPAD does not | provide built-in support for calling functions with optional | arguments. Instead what it does is collect all the arguments | containing == into a List *and* then it applies the name to the left | of == as a function to the value on the right. So much to my surprize: Quite disgusting, no? | | (1) -> (x+->x)(sin==x,cos==y) | | (1) [sin(x),cos(y)] | | Type: List Expression Integer | | is equivalent to: | | (2) -> (x+->x)([sin(x),cos(y)]) | | (2) [sin(x),cos(y)] | | Type: List Expression Integer | | The list of optional arguments is always passed as the last argument | to the function. This is completely general so one can write for | example: | | (3) -> ((x,y)+->[x,y])(sin==x,n,cos==y) | | (3) [n,[sin(x),cos(y)]] | | Type: List Any | | What do you think? Do you like that, or is this something that should | be implemented in a deeper way? I don't like it: For example, I cannot '==' to mean `definition' in expressions -- but I already had that debate with Ralf. -- Gaby ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ open-axiom-devel mailing list open-axiom-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/open-axiom-devel
