Completely matches my opinion. Thanks. On 12.07.2016 20:36, tritium-list@sdamon.com wrote:
For better or worse, except for string literals which can be anything as long as you set a coding comment, python is pure ascii which simplifies everything. Lambda is not in the first 128 characters of Unicode, so it is highly unlikely to be accepted.
·‘Lambda’ is exactly as discouraging to type as it needs to be. A more likely to be accepted alternate keyword is ‘whyareyounotusingdef’
·Python doesn’t attempt to look like mathematical formula
·‘Lambda’ spelling is intuitive to most people who program
·TIMTOWTDI isn’t a religious edict. Python is more pragmatic than that.
·It’s hard to type in ALL editors unless your locale is set to (ancient?) Greek.
·… What are you doing to have an identifier outside of ‘[A-Za-z_][A-Za-z0-9_]+’?
*From:*Python-ideas [mailto:python-ideas-bounces+tritium-list=sdamon.com@python.org] *On Behalf Of *Stephan Houben *Sent:* Tuesday, July 12, 2016 8:38 AM *To:* python-ideas@python.org *Subject:* [Python-ideas] allow `lambda' to be spelled λ
Hi list,
Here is my speculative language idea for Python:
Allow the following alternative spelling of the keyword `lambda':
λ
(That is "Unicode Character 'GREEK SMALL LETTER LAMDA' (U+03BB).")
Background:
I have been using the Vim "conceal" functionality with a rule which visually
replaces lambda with λ when editing Python files. I find this a great improvement in
readability since λ is visually less distracting while still quite distinctive.
(The fact that λ is syntax-colored as a keyword also helps with this.)
However, at the moment the nice syntax is lost when looking at the file through another editor or viewer.
Therefore I would really like this to be an official part of the Python syntax.
I know people have been clamoring for shorter lambda-syntax in the past, I think this is
a nice minimal extension.
Example code:
lst.sort(key=lambda x: x.lookup_first_name())
lst.sort(key=λ x: x.lookup_first_name())
# Church numerals
zero = λ f: λ x: x
one = λ f: λ x: f(x)
two = λ f: λ x: f(f(x))
(Yes, Python is my favorite Scheme dialect. Why did you ask?)
Note that a number of other languages already allow this. (Racket, Haskell).
You can judge the aesthetics of this on your own code with the following sed command.
sed 's/\<lambda\>/λ/g'
Advantages:
* The lambda keyword is quite long and distracts from the "meat" of the lambda expression.
Replacing it by a single-character keyword improves readability.
* The resulting code resembles more closely mathematical notation (in particular, lambda-calculus notation),
so it brings Python closer to being "executable pseudo-code".
* The alternative spelling λ/lambda is quite intuitive (at least to anybody who knows Greek letters.)
Disadvantages:
For your convenience already noticed here:
* Introducing λ is introducing TIMTOWTDI.
* Hard to type with certain editors.
But note that the old syntax is still available.
Easy to fix by upgrading to VIM ;-)
* Will turn a pre-existing legal identifier λ into a keyword.
So backward-incompatible.
Needless to say, my personal opinion is that the advantages outweigh the disadvantages. ;-)
Greetings,
Stephan
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