Sketch input is plain ASCII text, usually stored in an input
file.
It describes a scene,
so the sketch language is a scene description
language.
Sketch input is also declarative.
It merely
declares what the scene ought to look like when drawing is complete
and says very little about how sketch should do its work.
Sketch commands are not executed sequentially as in the usual
programming language. They merely contribute to that declaration.
A few syntactic details are important. Case is significant in the
sketch language. With a few exceptions, white space is not.
This includes line breaks.
Comments begin with % or # and extend to the end of the
line. You can disable a chunk of syntactically correct sketch
code by enclosing it in a def.
There is a simple “include file” mechanism.
The command
input{otherfile.sk}
causes the contents of otherfile.sk to be inserted as though
they were part of the current file.