Allow default arguments #131
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
We typically define a function like this:
(set! hello1 (fn* (name)
(print "Hello %s" name)))
Here we say there is a parameter "name" which must be supplied, and that
is later used.
If we instead say that parameters can be lists we can allow the first
value to be the name, and the second a default value if nothing is
actually passed, like so:
(set! hello2 (fn* ( (name "World") )
(print "Hello %s" name)))
These could be used like so:
(hello1 "Steve") ; "Hello Steve"
(hello2 "Steve") ; "Hello Steve"
(hello2) ; "Hello World"
I've not yet experimented with supplying defaults in the non-final
arguments, because that could screw things up. But for simple cases
like the one above it seems to work.
Once complete this will close #130, however I need to add test-cases..
Inc/Dec increase/decrease a value by one, but now we add a parameter which controls how much to add/sub, and make it default to 1. This means: (inc 1 ) ; 2 (inc 1 19) ; 20 Similarly dec: (dec 10 ) ; 9 (dec 10 2) ; 8
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
We typically define a function like this:
Here we say there is a parameter "name" which must be supplied, and that is later used.
If we instead say that parameters can be lists we can allow the first value to be the name, and the second a default value if nothing is actually passed, like so:
These could be used like so:
I've not yet experimented with supplying defaults in the non-final arguments, because that could screw things up. But for simple cases like the one above it seems to work.
Once complete this will close #130, however I need to add test-cases..