Pyli/Methods/Sequence

Sequences

These are useful for any kind of type that has contents, such as strings, vectors, and dicts.

• (empty? seq): Return True if a contains no items, False otherwise.
• (length seq): Return the number of items in a.
• (el seq index): Return the item of seq at the index.
• (sub seq start [end]): Return the sub sequence of the seq starting from start to end.

These will generate sequences.

• (range x [y [z]]):
  • (range x): 0 to (x-1)
  • (range x y): x to (y-1)
  • (range x y z): x to (y-1) step z
• (from x [step z]): Starts at x and goes on forever.
• (to x [step z]): Starts at 0 and goes on to x-1.
• (from x to y [step z]): x to (y-1) step z.

iter-fn

(iter-fn body ...)

iter-fn returns an iterator. (iter-fn.iter) returns itself.)

Calling (iter-fn.next) will call the body statements, one at a time, in the lexical environment they were defined in. The result is returned. It a stop-iteration is signalled, then that will be passed on.

iter-named-fn

(iter-named-fn name body ...)

Like iter-fn, but the next method has a name of 'name'.

map

• (map fn a)

Returns an iterator that will apply fn to a.next before yielding it.

zip

• (zip a b ...)

Returns an iterator that will yield (a.next b.next ...).