Livescript is Updated

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descientist 2015-10-19 19:31:43 +05:30
parent b86ea4d51d
commit 9f609e23e6

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@ -22,7 +22,8 @@ Feedback is always welcome, so feel free to reach me over at
[@kurisuwhyte](https://twitter.com/kurisuwhyte) :)
```coffeescript
coffeescript
------------
# Just like its CoffeeScript cousin, LiveScript uses number symbols for
# single-line comments.
@ -30,8 +31,9 @@ Feedback is always welcome, so feel free to reach me over at
Multi-line comments are written C-style. Use them if you want comments
to be preserved in the JavaScript output.
*/
```
```coffeescript
coffeescript
------------
# As far as syntax goes, LiveScript uses indentation to delimit blocks,
# rather than curly braces, and whitespace to apply functions, rather
# than parenthesis.
@ -42,12 +44,11 @@ Feedback is always welcome, so feel free to reach me over at
########################################################################
# Lack of value is defined by the keyword `void` instead of `undefined`
void # same as `undefined` but safer (can't be overridden)
void ,same as `undefined` but safer (can't be overridden)
# No valid value is represented by Null.
null
# The most basic actual value is the logical type:
true
false
@ -56,10 +57,9 @@ false
on; off
yes; no
# Then you get numbers. These are double-precision floats like in JS.
10
0.4 # Note that the leading `0` is required
0.4,Note that the leading `0` is required
# For readability, you may use underscores and letter suffixes in a
# number, and these will be ignored by the compiler.
@ -67,7 +67,7 @@ yes; no
# Strings are immutable sequences of characters, like in JS:
"Christina" # apostrophes are okay too!
"Christina", apostrophes are okay too!
"""Multi-line
strings
are
@ -76,7 +76,7 @@ yes; no
# Sometimes you want to encode a keyword, the backslash notation makes
# this easy:
\keyword # => 'keyword'
\keyword # => 'keyword'
# Arrays are ordered collections of values.
@ -93,7 +93,7 @@ fruits = [ \apple, \orange, \pear ]
fruits = <[ apple orange pear ]>
# You can retrieve an item by their 0-based index:
fruits[0] # => "apple"
fruits[0] # => "apple"
# Objects are a collection of unordered key/value pairs, and a few other
# things (more on that later).
@ -107,19 +107,19 @@ person =
person = {name: "Christina", likes: ["kittens", "and other cute stuff"]}
# You can retrieve an item by their key:
person.name # => "Christina"
person["name"] # => "Christina"
person.name # => "Christina"
person["name"] # => "Christina"
# Regular expressions use the same syntax as JavaScript:
trailing-space = /\s$/ # dashed-words become dashedWords
trailing-space = /\s$/ # dashed-words become dashedWords
# Except you can do multi-line expressions too!
# (comments and whitespace just gets ignored)
funRE = //
function\s+(.+) # name
\s* \((.*)\) \s* # arguments
{ (.*) } # body
function\s+(.+) # name
\s* \((.*)\) \s* # arguments
{ (.*) } # body
//
@ -134,7 +134,6 @@ funRE = //
4 / 2 # => 2
3 % 2 # => 1
# Comparisons are mostly the same too, except that `==` is the same as
# JS's `===`, where JS's `==` in LiveScript is `~=`, and `===` enables
# object and array comparisons, and also stricter comparisons:
@ -185,7 +184,6 @@ two!
# The `:=` operator is available to *reuse* a name from the parent
# scope.
# You can destructure arguments of a function to quickly get to
# interesting values inside a complex data structure:
tail = ([head, ...rest]) -> rest
@ -194,7 +192,7 @@ tail [1, 2, 3] # => [2, 3]
# You can also transform the arguments using binary or unary
# operators. Default arguments are also possible.
foo = (a = 1, b = 2) -> a + b
foo! # => 3
foo! # => 3
# You could use it to clone a particular argument to avoid side-effects,
# for example:
@ -205,24 +203,22 @@ a = { a: 1 }
copy a, { b: 2 } # => { a: 1, b: 2 }
a # => { a: 1 }
# A function may be curried by using a long arrow rather than a short
# one:
add = (left, right) --> left + right
add1 = add 1
add1 2 # => 3
add1 2 # => 3
# Functions get an implicit `it` argument, even if you don't declare
# any.
identity = -> it
identity 1 # => 1
identity 1 # => 1
# Operators are not functions in LiveScript, but you can easily turn
# them into one! Enter the operator sectioning:
divide-by-two = (/ 2)
[2, 4, 8, 16].map(divide-by-two) .reduce (+)
# Not only of function application lives LiveScript, as in any good
# functional language you get facilities for composing them:
double-minus-one = (- 1) . (* 2)
@ -233,11 +229,10 @@ double-minus-one = (- 1) . (* 2)
double-minus-one = (* 2) >> (- 1)
double-minus-one = (- 1) << (* 2)
# And talking about flow of value, LiveScript gets the `|>` and `<|`
# operators that apply a value to a function:
map = (f, xs) --> xs.map f
[1 2 3] |> map (* 2) # => [2 4 6]
[1 2 3] |> map (* 2) # => [2 4 6]
# You can also choose where you want the value to be placed, just mark
# the place with an underscore (_):
@ -251,7 +246,6 @@ div = (left, right) -> left / right
div-by-two = div _, 2
div-by-two 4 # => 2
# Last, but not least, LiveScript has back-calls, which might help
# with some callback-based code (though you should try more functional
# approaches, like Promises):
@ -263,7 +257,6 @@ console.log a + b
# Same as:
readFile 'foo', (a) -> readFile 'bar', (b) -> console.log a + b
########################################################################
## 4. Patterns, guards and control-flow
########################################################################
@ -290,7 +283,6 @@ take = (n, [x, ...xs]) -->
| n == 0 => []
| _ => [x] ++ take (n - 1), xs
########################################################################
## 5. Comprehensions
########################################################################
@ -309,7 +301,6 @@ evens = [x for x in oneToTwenty when x % 2 == 0]
# back an object rather than an Array:
copy = { [k, v] for k, v of source }
########################################################################
## 4. OOP
########################################################################