urbit/pub/docs/dev/hoon/library/2eb.md

section 2eB, parsing (tracing)

++last

Farther trace

++  last  |=  [zyc=hair naz=hair]                       ::  farther trace
          ^-  hair
          ?:  =(p.zyc p.naz)
            ?:((gth q.zyc q.naz) zyc naz)
          ?:((gth p.zyc p.naz) zyc naz)
::

Compares two line-column pairs, zyc and naz, and produces whichever hair is farther along.

zyc is a hair.

naz is a hair.

~zod/try=> (last [1 1] [1 2])
[p=1 q=2]
~zod/try=> (last [2 1] [1 2])
[p=2 q=1]
~zod/try=> (last [0 0] [99 0])
[p=99 q=0]
~zod/try=> (last [7 7] [7 7])
[p=7 q=7]

---

++lust

Detect newline

++  lust  |=  [weq=char naz=hair]                       ::  detect newline
          ^-  hair
          ?:(=(10 weq) [+(p.naz) 1] [p.naz +(q.naz)])

Advances the hair naz by a row if the char weq is a newline, or by a column if weq is any other character.

weq is a char.

naz is a hair.

~zod/try=> (lust `a` [1 1])
[p=1 q=2]
~zod/try=> (lust `@t`10 [1 1])
[p=2 q=1]
~zod/try=> (lust '9' [10 10])
[p=10 q=11]
/~zod/try=> (roll "maze" [.(+<+ [1 1])]:lust)
[1 5]
/~zod/try=> %-  roll  :_  [.(+<+ [1 1])]:lust
"""
Sam
lokes
"""
[2 6]

---