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ilo

Real-World Examples

Practical patterns you can copy and adapt. Each example is a complete, runnable program.

Data pipeline

Section titled “Data pipeline”

Fetch JSON from an API, filter positive values, sum them:

ilo
fetch url:t>R _ t;r=($!url);rdb! r "json"
pos x:_>b;>x 0
proc rows:L _>n;clean=flt pos rows;sum clean

Three functions, no boilerplate. $! auto-unwraps the HTTP response. rdb! parses JSON. flt keeps only elements where pos returns true.

API status checker

Section titled “API status checker”

Hit a URL and report whether it responded:

ilo
check url:t>t
  r=$url
  ?r{~v:fmt "{}: ok" url;^e:fmt "{}: {}" url e}
Shell
ilo 'check url:t>t;r=$url;?r{~v:fmt "{}: ok" url;^e:fmt "{}: {}" url e}' "http://httpbin.org/get"
# -> http://httpbin.org/get: ok

$url makes an HTTP GET. The result is matched: ~v (Ok) or ^e (Err).

CSV processing

Section titled “CSV processing”
Shell
# Column count of the first row
ilo 'f p:t>R n t;d=rd! p;~len d.0' f data.csv

rd! reads and parses the CSV file (returns R, so the function must too). d.0 indexes the first row.

Text processing

Section titled “Text processing”

Count unique words in a file:

Shell
ilo 'f p:t>R n t;t=rd! p "raw";ws=spl t " ";~len (unq ws)' f document.txt

Extract all emails from text:

Shell
ilo 'f s:t>L t;rgx "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}" s' \
  "contact alice@example.com or bob@test.org"
# -> [alice@example.com, bob@test.org]

Sort words by length:

ilo
wlen s:t>n;len s
by-len ws:L t>L t;srt wlen ws
Shell
ilo examples/sort-by-key.ilo by-len '["banana","fig","apple","kiwi"]'
# -> ["fig", "kiwi", "apple", "banana"]

Environment config

Section titled “Environment config”

Read an env var with a fallback:

ilo
cfg>t
  k=env "API_KEY"
  ?k{~v:v;^e:"missing API_KEY"}

env returns a Result. The match provides the value or a default.

Tool interaction

Section titled “Tool interaction”

Declare external tools, then compose them like regular functions:

ilo
tool get-user"Retrieve user by ID" uid:t>R profile t timeout:5,retry:2
tool send-email"Send notification email" to:t subject:t body:t>R _ t timeout:10,retry:1


type profile{id:t;name:t;email:t;verified:b}


notify uid:t msg:t>R _ t
  u=get-user! uid
  !u.verified{^"user not verified"}
  send-email! u.email "Notification" msg
  ~_

Tools are type-checked at compile time. get-user! unwraps the result, propagating errors automatically.

Python vs ilo

Section titled “Python vs ilo”

A tax-inclusive total calculation in both languages.

Python (93 chars, ~30 tokens):

Python
def total(price: float, quantity: int, rate: float) -> float:
    sub = price * quantity
    tax = sub * rate
    return sub + tax

ilo (38 chars, ~10 tokens):

ilo
tot p:n q:n r:n>n;s=*p q;t=*s r;+s t

Same semantics. 0.33x the tokens, 0.22x the characters. For an AI agent paying per token, this adds up fast across thousands of tool calls.

What’s next

Section titled “What’s next”