Lambda - NDC Conference - Kevlin Henney
Table of Contents
1. Lambda => No problem of naming things ;)
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Despite the fancy name, a lambda is just a function… peculiarly… without a name.
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There are only two hard things in Computer Science: cache invalidation and naming things.
- Phil Karlton
2. Scheme (Origin story for its name)
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There were academic languages: Planner, Mapper and a newer one was being made called Schemer. But there was 6 character limit on file name so Schemer became Scheme
3. Objects and Closures : A Zen Koan
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http://people.csail.mit.edu/gregs/ll1-discuss-archive-html/msg03277.html
The venerable master Qc Na was walking with his student, Anton. Hoping to prompt the master into a discussion, Anton said "Master, I have heard that objects are a very good thing - is this true?" Qc Na looked pityingly at his student and replied, "Foolish pupil - objects are merely a poor man's closures."
Chastised, Anton took his leave from his master and returned to his cell, intent on studying closures. He carefully read the entire "Lambda: The Ultimate…" series of papers and its cousins, and implemented a small Scheme interpreter with a closure-based object system. He learned much, and looked forward to informing his master of his progress.
On his next walk with Qc Na, Anton attempted to impress his master by saying "Master, I have diligently studied the matter, and now understand that objects are truly a poor man's closures." Qc Na responded by hitting Anton with his stick, saying "When will you learn? Closures are a poor man's object." At that moment, Anton became enlightened.
4. Closure in C++
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< Collapse code block
[](){};
This is a lambda that captures nothing, takes no argument, and does nothing. And
< Collapse code block
[](){}();
this is how you execute it.
5. Lambdas in Java and C# are not true lambdas
because they don't support application. (i.e. funcall)
No way to apply an empty lambda. This is not possible.
() => {} ();
