Legacy debug commands

The legacy log, say, warn and error commands, where their output went in originOS, and how each works in compiled OSL.

In originOS, four commands inspected a running script: log, say, warn and error. They wrote to the browser's developer console. In compiled OSL they still exist, and write to the terminal instead. log and say behave as before. warn and error now write to standard error.

log and say#

log printed any value so you could see it while developing. It is OSL's print. say was an alias:

log "hello world"
say "same as log"

The output format has not changed. Strings print as they are. Numbers and booleans print as written. Arrays and objects print as JSON, with objects' keys in sorted order:

log "hello world"
say "same as log"
log 42
log [1, 2, 3]
log {a: 1, b: 2}
log true

log takes any number of values and prints them separated by spaces. Commas between them are a syntax error. To build one string with no spaces, join with ++, which turns the other value into text:

int x = 5
log "x is " ++ x
log "a" "b" 3

warn and error#

warn and error took the same arguments as log, and differed only in where the message went. In originOS, they sent a warning or an error to the browser console, where it appeared with a yellow or red mark:

warn "im warning you >:("
error "something went wrong!!"

The two names signal intent, and nothing else. Neither stopped the script. To stop it, use throw.

In compiled OSL, both write to standard error, so they stay out of a program's normal output and can be redirected on their own:

log "result"             // standard output
warn "low on memory"     // standard error
error "request failed"   // standard error

osl run job.osl > result.txt          # only log goes to the file
osl run job.osl 2> problems.txt       # only warn and error go to the file

Levelled logging#

For logs with levels, timestamps and history, use std:log. It has log.debug, log.info, log.success, log.error, log.fatal and more:

import "std:log"

log.info("server started")
log.error("request failed")

What to use now#