generate ac source for underscore.js from document

aa-screenshot.png

ab-generate-ac-source-underscore.js

(function (doc) {
    let helps = {};

    function recordDoc(k, doc) helps[k] = doc;
    function chomp(s) s.replace(/^[ \t\n\r]+/, "").replace(/[ \t\n\r]+$/, "");
    function esc(s) s.replace(/(?!\\)"/g, '\\"');
    function quote(s) '"' + s + '"';

    Array.forEach(doc.querySelectorAll("#documentation > p[id]"), function (_p) {
        let p = _p.cloneNode(true);

        let headName = p.removeChild(p.querySelector("b.header")).textContent;
        let aliases = let (cand = p.querySelector("span.alias")) (
            cand ? p.removeChild(cand).querySelector("b")
                .textContent.split(/,[ ]*/)
                : []
        );

        let names = [headName].concat(aliases);

        let helpLines = chomp(p.textContent)
            .split("\n")
            .map(chomp)
            .filter(function (l) l.length)
            .map(esc);
        let helpTitle = helpLines.shift();
        let helpBody  = helpLines.join("\n");

        function getProperHelpTitle(name) helpTitle
            .replace(/(_\.)(?:[a-zA-Z_$][a-zA-Z_$0-9]*)(.*)/, "$1" + name + "$2");

        names.forEach(function (name) {
            helps[name] = getProperHelpTitle(name) + "\n\n" + helpBody;
        });
    });

    return ["(" + quote(name) + " . " + quote(help) + ")"
            for ([name, help] in Iterator(helps))].join("\n");
})(document);

ac-source-underscore-js.el

(add-hook 'js2-mode-hook
          (lambda ()
            (define-key js2-mode-map (kbd ".") 'js2usj-insert-dot)))

;; ============================================================ ;;
;; Settings for eldoc
;; ============================================================ ;;

(defun underscore-js-turn-on-eldoc-mode ()
  "Enable underscore-js-eldoc-mode"
  (interactive)
  (set (make-local-variable 'eldoc-documentation-function)
       'underscore-js-print-function-signature)
  (turn-on-eldoc-mode))

(defun underscore-js-print-function-signature ()
  "Returns documentation string for the current symbol."
  (when
      (save-excursion
        (re-search-backward
         "\\(?:^\\|[^a-zA-Z_$]\\)\\([a-zA-Z_$][a-zA-Z0-9_$]*\\)[ ]*("
         (point-min) t))
    (let* ((pair
            (assoc (match-string 1) ac-underscore-js-doc-alist))
           (doc (and pair
                     (nth 0 (split-string (cdr pair) "\n")))))
      (when doc
        (eldoc-message doc)))))

;; ============================================================ ;;

(defsubst js2usj-dotted-node-p (node)
  (and node
       (or (js2-prop-get-node-p node)
           (js2-call-node-p node))))

(defsubst js2usj-get-dotted-node-left (node)
  (cond
   ((js2-prop-get-node-p node)
    (js2-prop-get-node-left node))
   ((js2-call-node-p node)
    (js2-call-node-target node))))

(defun js2usj-get-leftmost-name-node ()
  (let ((node (js2-node-at-point)))
    (when (and (js2-name-node-p node)
               (js2usj-dotted-node-p (js2-name-node-parent node)))
      (setq node (js2-name-node-parent node)))
    (while (js2usj-dotted-node-p node)
      (setq node (js2usj-get-dotted-node-left node)))
    (and (js2-name-node-p node) node)))

(defun js2usj-insert-dot ()
  (interactive)
  (let ((leftmost (save-excursion
                    (search-backward-regexp "[^ \t\n\r]" (point-min) t)
                    (js2usj-get-leftmost-name-node))))
    (insert ".")
    (when (and leftmost
               (equal (js2-name-node-name leftmost) "_"))
      (auto-complete '(ac-source-underscore-js)))))

(defvar ac-source-underscore-js
      '((cache)
        (prefix "\\.\\(\\(?:[a-zA-Z_$][a-zA-Z0-9_$]*\\)?\\)" nil 1)
        (candidates . (lambda ()
                        (loop for (name . doc) in ac-underscore-js-doc-alist
                              collect name)))
        (document . (lambda (sym)
                      (cdr (assoc sym ac-underscore-js-doc-alist))))
        (requires . 0)))

(defvar ac-underscore-js-doc-alist
  '(("each" . "_.each(list, iterator, [context])

Iterates over a list of elements, yielding each in turn to an iterator
function. The iterator is bound to the context object, if one is
passed. Each invocation of iterator is called with three arguments:
\(element, index, list). If list is a JavaScript object, iterator's
arguments will be (value, key, list). Delegates to the native
forEach function if it exists.")
    ("forEach" . "_.forEach(list, iterator, [context])

Iterates over a list of elements, yielding each in turn to an iterator
function. The iterator is bound to the context object, if one is
passed. Each invocation of iterator is called with three arguments:
\(element, index, list). If list is a JavaScript object, iterator's
arguments will be (value, key, list). Delegates to the native
forEach function if it exists.")
    ("map" . "_.map(list, iterator, [context])

Produces a new array of values by mapping each value in list
through a transformation function (iterator). If the native map method
exists, it will be used instead. If list is a JavaScript object,
iterator's arguments will be (value, key, list).")
    ("reduce" . "_.reduce(list, iterator, memo, [context])

Also known as inject and foldl, reduce boils down a
list of values into a single value. Memo is the initial state
of the reduction, and each successive step of it should be returned by
iterator.")
    ("inject" . "_.inject(list, iterator, memo, [context])

Also known as inject and foldl, reduce boils down a
list of values into a single value. Memo is the initial state
of the reduction, and each successive step of it should be returned by
iterator.")
    ("foldl" . "_.foldl(list, iterator, memo, [context])

Also known as inject and foldl, reduce boils down a
list of values into a single value. Memo is the initial state
of the reduction, and each successive step of it should be returned by
iterator.")
    ("reduceRight" . "_.reduceRight(list, iterator, memo, [context])

The right-associative version of reduce. Delegates to the
JavaScript 1.8 version of reduceRight, if it exists. Foldr
is not as useful in JavaScript as it would be in a language with lazy
evaluation.")
    ("foldr" . "_.foldr(list, iterator, memo, [context])

The right-associative version of reduce. Delegates to the
JavaScript 1.8 version of reduceRight, if it exists. Foldr
is not as useful in JavaScript as it would be in a language with lazy
evaluation.")
    ("detect" . "_.detect(list, iterator, [context])

Looks through each value in the list, returning the first one that
passes a truth test (iterator). The function returns as
soon as it finds an acceptable element, and doesn't traverse the
entire list.")
    ("select" . "_.select(list, iterator, [context])

Looks through each value in the list, returning an array of all
the values that pass a truth test (iterator). Delegates to the
native filter method, if it exists.")
    ("filter" . "_.filter(list, iterator, [context])

Looks through each value in the list, returning an array of all
the values that pass a truth test (iterator). Delegates to the
native filter method, if it exists.")
    ("reject" . "_.reject(list, iterator, [context])

Returns the values in list without the elements that the truth
test (iterator) passes. The opposite of select.")
    ("all" . "_.all(list, [iterator], [context])

Returns true if all of the values in the list pass the iterator
truth test. If an iterator is not provided, the truthy value of
the element will be used instead. Delegates to the native method every, if
present.")
    ("every" . "_.every(list, [iterator], [context])

Returns true if all of the values in the list pass the iterator
truth test. If an iterator is not provided, the truthy value of
the element will be used instead. Delegates to the native method every, if
present.")
    ("any" . "_.any(list, [iterator], [context])

Returns true if any of the values in the list pass the
iterator truth test. Short-circuits and stops traversing the list
if a true element is found. Delegates to the native method some,
if present.")
    ("some" . "_.some(list, [iterator], [context])

Returns true if any of the values in the list pass the
iterator truth test. Short-circuits and stops traversing the list
if a true element is found. Delegates to the native method some,
if present.")
    ("include" . "_.include(list, value)

Returns true if the value is present in the list, using
=== to test equality. Uses indexOf internally, if list
is an Array.")
    ("contains" . "_.contains(list, value)

Returns true if the value is present in the list, using
=== to test equality. Uses indexOf internally, if list
is an Array.")
    ("invoke" . "_.invoke(list, methodName, [*arguments])

Calls the method named by methodName on each value in the list.
Any extra arguments passed to invoke will be forwarded on to the
method invocation.")
    ("pluck" . "_.pluck(list, propertyName)

An convenient version of what is perhaps the most common use-case for
map: extracting a list of property values.")
    ("max" . "_.max(list, [iterator], [context])

Returns the maximum value in list. If iterator is passed,
it will be used on each value to generate the criterion by which the
value is ranked.")
    ("min" . "_.min(list, [iterator], [context])

Returns the minimum value in list. If iterator is passed,
it will be used on each value to generate the criterion by which the
value is ranked.")
    ("sortBy" . "_.sortBy(list, iterator, [context])

Returns a sorted list, ranked by the results of running each
value through iterator.")
    ("sortedIndex" . "_.sortedIndex(list, value, [iterator])

Uses a binary search to determine the index at which the value
should be inserted into the list in order to maintain the list's
sorted order. If an iterator is passed, it will be used to compute
the sort ranking of each value.")
    ("toArray" . "_.toArray(list)

Converts the list (anything that can be iterated over), into a
real Array. Useful for transmuting the arguments object.")
    ("size" . "_.size(list)

Return the number of values in the list.")
    ("first" . "_.first(array, [n])

Returns the first element of an array. Passing n will
return the first n elements of the array.")
    ("head" . "_.head(array, [n])

Returns the first element of an array. Passing n will
return the first n elements of the array.")
    ("rest" . "_.rest(array, [index])

Returns the rest of the elements in an array. Pass an index
to return the values of the array from that index onward.")
    ("tail" . "_.tail(array, [index])

Returns the rest of the elements in an array. Pass an index
to return the values of the array from that index onward.")
    ("last" . "_.last(array)

Returns the last element of an array.")
    ("compact" . "_.compact(array)

Returns a copy of the array with all falsy values removed.
In JavaScript, false, null, 0, \"\",
undefined and NaN are all falsy.")
    ("flatten" . "_.flatten(array)

Flattens a nested array (the nesting can be to any depth).")
    ("without" . "_.without(array, [*values])

Returns a copy of the array with all instances of the values
removed. === is used for the equality test.")
    ("uniq" . "_.uniq(array, [isSorted])

Produces a duplicate-free version of the array, using === to test
object equality. If you know in advance that the array is sorted,
passing true for isSorted will run a much faster algorithm.")
    ("unique" . "_.unique(array, [isSorted])

Produces a duplicate-free version of the array, using === to test
object equality. If you know in advance that the array is sorted,
passing true for isSorted will run a much faster algorithm.")
    ("intersect" . "_.intersect(*arrays)

Computes the list of values that are the intersection of all the arrays.
Each value in the result is present in each of the arrays.")
    ("zip" . "_.zip(*arrays)

Merges together the values of each of the arrays with the
values at the corresponding position. Useful when you have separate
data sources that are coordinated through matching array indexes.")
    ("indexOf" . "_.indexOf(array, value, [isSorted])

Returns the index at which value can be found in the array,
or -1 if value is not present in the array. Uses the native
indexOf function unless it's missing. If you're working with a
large array, and you know that the array is already sorted, pass true
for isSorted to use a faster binary search.")
    ("lastIndexOf" . "_.lastIndexOf(array, value)

Returns the index of the last occurrence of value in the array,
or -1 if value is not present. Uses the native lastIndexOf
function if possible.")
    ("range" . "_.range([start], stop, [step])

A function to create flexibly-numbered lists of integers, handy for
each and map loops. start, if omitted, defaults
to 0; step defaults to 1. Returns a list of integers
from start to stop, incremented (or decremented) by step,
exclusive.")
    ("bind" . "_.bind(function, object, [*arguments])

Bind a function to an object, meaning that whenever
the function is called, the value of this will be the object.
Optionally, bind arguments to the function to pre-fill them,
also known as currying.")
    ("bindAll" . "_.bindAll(object, [*methodNames])

Binds a number of methods on the object, specified by
methodNames, to be run in the context of that object whenever they
are invoked. Very handy for binding functions that are going to be used
as event handlers, which would otherwise be invoked with a fairly useless
this. If no methodNames are provided, all of the object's
function properties will be bound to it.")
    ("memoize" . "_.memoize(function, [hashFunction])

Memoizes a given function by caching the computed result. Useful
for speeding up slow-running computations. If passed an optional
hashFunction, it will be used to compute the hash key for storing
the result, based on the arguments to the original function.")
    ("delay" . "_.delay(function, wait, [*arguments])

Much like setTimeout, invokes function after wait
milliseconds. If you pass the optional arguments, they will be
forwarded on to the function when it is invoked.")
    ("defer" . "_.defer(function)

Defers invoking the function until the current call stack has cleared,
similar to using setTimeout with a delay of 0. Useful for performing
expensive computations or HTML rendering in chunks without blocking the UI thread
from updating.")
    ("throttle" . "_.throttle(function, wait)

Returns a throttled version of the function, that, when invoked repeatedly,
will only actually call the wrapped function at most once per every wait
milliseconds. Useful for rate-limiting events that occur faster than you
can keep up with.")
    ("debounce" . "_.debounce(function, wait)

Repeated calls to a debounced function will postpone it's execution
until after wait milliseconds have elapsed. Useful for implementing
behavior that should only happen after the input has stopped arriving.
For example: rendering a preview of a Markdown comment, recalculating a
layout after the window has stopped being resized...")
    ("wrap" . "_.wrap(function, wrapper)

Wraps the first function inside of the wrapper function,
passing it as the first argument. This allows the wrapper to
execute code before and after the function runs, adjust the arguments,
and execute it conditionally.")
    ("compose" . "_.compose(*functions)

Returns the composition of a list of functions, where each function
consumes the return value of the function that follows. In math terms,
composing the functions f(), g(), and h() produces
f(g(h())).")
    ("keys" . "_.keys(object)

Retrieve all the names of the object's properties.")
    ("values" . "_.values(object)

Return all of the values of the object's properties.")
    ("functions" . "_.functions(object)

Returns a sorted list of the names of every method in an object —
that is to say, the name of every function property of the object.")
    ("methods" . "_.methods(object)

Returns a sorted list of the names of every method in an object —
that is to say, the name of every function property of the object.")
    ("extend" . "_.extend(destination, *sources)

Copy all of the properties in the source objects over to the
destination object. It's in-order, to the last source will override
properties of the same name in previous arguments.")
    ("clone" . "_.clone(object)

Create a shallow-copied clone of the object. Any nested objects
or arrays will be copied by reference, not duplicated.")
    ("tap" . "_.tap(object, interceptor)

Invokes interceptor with the object, and then returns object.
The primary purpose of this method is to \"tap into\" a method chain, in order to perform operations on intermediate results within the chain.")
    ("isEqual" . "_.isEqual(object, other)

Performs an optimized deep comparison between the two objects, to determine
if they should be considered equal.")
    ("isEmpty" . "_.isEmpty(object)

Returns true if object contains no values.")
    ("isElement" . "_.isElement(object)

Returns true if object is a DOM element.")
    ("isArray" . "_.isArray(object)

Returns true if object is an Array.")
    ("isArguments" . "_.isArguments(object)

Returns true if object is an Arguments object.")
    ("isFunction" . "_.isFunction(object)

Returns true if object is a Function.")
    ("isString" . "_.isString(object)

Returns true if object is a String.")
    ("isNumber" . "_.isNumber(object)

Returns true if object is a Number.")
    ("isBoolean" . "_.isBoolean(object)

Returns true if object is either true or false.")
    ("isDate" . "_.isDate(object)

Returns true if object is a Date.")
    ("isRegExp" . "_.isRegExp(object)

Returns true if object is a RegExp.")
    ("isNaN" . "_.isNaN(object)

Returns true if object is NaN. Note: this is not
the same as the native isNaN function, which will also return
true if the variable is undefined.")
    ("isNull" . "_.isNull(object)

Returns true if the value of object is null.")
    ("isUndefined" . "_.isUndefined(variable)

Returns true if variable is undefined.")
    ("noConflict" . "_.noConflict()

Give control of the \"_\" variable back to its previous owner. Returns
a reference to the Underscore object.")
    ("identity" . "_.identity(value)

Returns the same value that is used as the argument. In math:
f(x) = x
This function looks useless, but is used throughout Underscore as
a default iterator.")
    ("times" . "_.times(n, iterator)

Invokes the given iterator function n times.")
    ("mixin" . "_.mixin(object)

Allows you to extend Underscore with your own utility functions. Pass
a hash of {name: function} definitions to have your functions
added to the Underscore object, as well as the OOP wrapper.")
    ("uniqueId" . "_.uniqueId([prefix])

Generate a globally-unique id for client-side models or DOM elements
that need one. If prefix is passed, the id will be appended to it.")
    ("template" . "_.template(templateString, [context])

Compiles JavaScript templates into functions that can be evaluated
for rendering. Useful for rendering complicated bits of HTML from JSON
data sources. Template functions can both interpolate variables, using
<%= … %>, as well as execute arbitrary JavaScript code, with
<% … %>. When you evaluate a template function, pass in a
context object that has properties corresponding to the template's free
variables. If you're writing a one-off, you can pass the context
object as the second parameter to template in order to render
immediately instead of returning a template function.")
    ("chain" . "_(obj).chain()

Returns a wrapped object. Calling methods on this object will continue
to return wrapped objects until value is used. (
A more realistic example.)")
    ("value" . "_(obj).value()

Extracts the value of a wrapped object.")))