[bp-dev] We need a "Play" command

[Bernard B. <ber...@gm...>]

Dear Anthony,

I notice that you created a vocabulary of "actions" such as 'produce', 
'compile' etc. This is a very good idea. On the PHP interface I will 
create a template containing syntactic rules for creating correct line 
commands. Thus it will be eay to adapt the interface to modified/new 
rules without fiddling with PHP code.

I am now half-way on the editor of sound-object prototypes. The editor 
is already able to interpret a ‘-mi’ file, identify soud-objects, 
display their properties and modify a few parameters. Displaying 
parameters requires lengthy programming because they are all stored as 
integer numbers and need to be handled with checkboxes, radiobuttons etc.

Graphic display will be missing but I started thinking about a HTML 
display that might be as informative as the old display (see attached 
picture of the old display).

On the interface we had buttons ‘Play object alone’ and ‘Play 
expression’. We'll keep them. To this effect we need a ‘play’ command.

In BP2.9.8 all ‘play’ actions were handled by PlaySelection(). You can 
use this procedure, replacing the selection with the content of a data 
file. Basically the call would be:

     ./bp play somepath/somedatafile

However, to play the content of a data file, the machine needs an 
alphabet and optionaly a sound-object prototype file. So, unless these 
are identified on top of the datafile (which we agreed is not a good 
idea) the command would be:

     ./bp play somepath/somedatafile somepath/somealphabetfile 
somepath/somesoundobjectprototypefile

There is more than that: PlaySelection() will analyze the selection and 
possibly find variables. If variables are found, it requires a grammar 
to derive them. In fact, it takes the selection (or the input) as a 
start string and runs the "produce" command. So we may have a more 
detailed command such as:

     ./bp play somepath/somedatafile somepath/somegrammarfile 
somepath/somealphabetfile somepath/somesounsobjectprototypefile

Plus perhaps options to play in real midi or create a MIDI or Csound file…

You can decide that the ‘play’ command always takes data as a 
startstring and sends it to the grammar for computation. If there is no 
grammar or no variable in the string, then computation will return the 
startstring. So you don't need to bother whether the string contains 
variables or not.

I am certainly anticipating your agenda but it is safe to include these 
expressions in syntax rules.

Bernard