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Matching variable-term equations

I am trying to develop a regular expression to match the following equations:
(Price+10%+100+200)
(Price+20%+200)
(Price+30%)
(Price+100)
(Price-10%-100-200)
(Price-20%-200)
(Price-30%)
(Price-100)
My regex so far is...
/([(])+([P])+([r])+([i])+([c])+([e])+([+]|[-]){1}([\d])+([+]|[-])?([\d])+([%])?([)])/g
..., but it only matches the following equations:
(Price+100+10%)
(Price+100+100)
(Price+200)
(Price-100-10%)
(Price-100-100)
(Price-200)
Can someone help me understand how to make my pattern match the full set of equations provided?
Note: Parentheses and 'Price' are musts in the equations that the pattern must match.

Try this, which matches all the input strings provided in the question:
/\(Price([+-]\d+%?){1,3}\)/g
You can test it in a regex fiddle.
Things to note:
Only use parentheses where you want to group. Parentheses around single-possibility, fixed-quantity matches (e.g. ([P]) provide no value.
Use character classes (opened with [ and closed with ]) for multiple characters that can match at a position in the pattern (e.g. [+-]). Single-possibility character classes (e.g. [P]) similarly provide no value.
Yes, character classes (generally) implicitly escape regex special characters within them (e.g. ( in [(] vs. equivalent \( outside a character class), but to just escape regex special characters (i.e. to match them literally), you are better off not using a character class and just escaping them (e.g. \() – unless multiple characters should match at a position in the pattern (per the previous point to note).
The quantifier {1} is (almost) always useless: drop it.
The quantifier + means "one or more" as you probably know. However, in a series of cases where you used it (i.e. ([(])+([P])+([r])+([i])+([c])+([e])+), it would match many values that I doubt you expect (e.g. ((((((PPPrriiiicccceeeeee): basically, don't overuse it. Stop to consider whether you really want to match one or more of the character (class) or group to which + applies in the pattern.
To match a literal string without any regex special characters like Price, just use the literal string at the appropriate position in the pattern – e.g. Price in \(Price.

/\(Price[+-](\d)+(%)?([+-]\d+%?)?([+-]\d+%?)?\)/g
works on http://www.regexr.com/

/^[(Price]+\d+\d+([%]|[)])&/i
try at your own risk!

What is this "/\,$/"?

Tried to search for /\,$/ online, but coudnt find anything.
I have:
coords = coords.replace(/\,$/, "");
Im guessing it returns coords string index number. What I have to search online for this, so I can learn more?

/\,$/ finds the comma character (,) at the end of a string (denoted by the $) and replaces it with empty (""). You sometimes see this in regex code aiming to clean up excerpts of text.

It's a regular expression to remove a trailing comma.

That thing is a Regular Expression, also known as regex or regexp. It is a way to "match" strings using some rules. If you want to learn how to use it in JavaScript, read the Mozilla Developer Network page about RegExp.
By the way, regular expressions are also available on most languages and in some tools. It is a very useful thing to learn.

That's a regular expression that finds a comma at the end of a string. That code removes the comma.

// defines a JavaScript regular expression, used to match a pattern within a string.
\,$ is the pattern
In this case \, translates to ,. A backslash is used to escape special characters, but in this case, it's not necessary. An example where it would be necessary would be to remove trailing periods. If you tried to do that with /.$/ the period here has a different meaning; it is used as a wildcard to match [almost] any character (aside for some newlines). So in this case to match on "." (period character) you would have to escape the wildcard (/\.$/).
When $ is placed at the end of the pattern, it means only look at the end of the string. This means that you can't mistakingly find a comma anywhere in the middle of the string (e.g., not after help in help, me,), only at the end (trailing). It also speeds of the regular expression search considerably. If you wanted to match on characters only at the beginning of the string, you would start off the pattern with a carat (^), for instance /^,/ would find a comma at the start of a string if one existed.
It's also important to note that you're only removing one comma, whereas if you use the plus (+) after the comma, you'd be replacing one or more: /,+$/.
Without the +; trailing commas,, becomes trailing commas,
With the +; no trailing comma,, becomes no trailing comma

Match simple regex pattern using JS (key: value)

I have a simple scenario where I want to match the follow and capture the value:
stuff_in_string,
env: 'local', // want to match this and capture the content in quotes
more_stuff_in_string
I have never written a regex pattern before so excuse my attempt, I am well aware it is totally wrong.
This is what I am trying to say:
Match "env:"
Followed by none or more spaces
Followed by a single or double quote
Capture all until..
The next single or double quote
/env:*?\s+('|")+(.*?)+('|")/g
Thanks
PS here is a #failed fiddle: http://jsfiddle.net/DfHge/
Note: this is the regex I ended up using (not the answer below as it was overkill for my needs): /env:\s+(?:"|')(\w+)(?:"|')/

You can use this:
/\benv: (["'])([^"']*)\1/g
where \1 is a backreference to the first capturing group, thus your content is in the second. This is the simple way for simple cases.
Now, other cases like:
env: "abc\"def"
env: "abc\\"
env: "abc\\\def"
env: "abc'def"
You must use a more constraining pattern:
first: avoid the different quotes problem:
/\benv: (["'])((?:[^"']+|(?!\1)["'])*)\1/g
I put all the possible content in a non capturing group that i can repeat at will, and I use a negative lookahead (?!\1) to check if the allowed quote is not the same as the captured quote.
second: the backslash problem:
If a quote is escaped, it can't be the closing quote! Thus you must check if the quote is escaped or not and allow escaped quotes in the string.
I remove the backslashes from allowed content:
/\benv: (["'])((?:[^"'\\]+|(?!\1)["'])*)\1/g
I allow escaped characters:
/\benv: (["'])((?:[^"'\\]+|(?!\1)["']|\\[\s\S])*)\1/g
To allow a variable number of spaces before the quoted part, you can replace : by :\s*
/\benv:\s*(["'])((?:[^"'\\]+|(?!\1)["']|\\[\s\S])*)\1/g
You have now a working pattern.
third: pattern optimization
a simple alternation:
Using a capture group and a backreferences can be seducing to deal with the different type of quotes since it allow to write the pattern in a concise way. However, this way needs to create a capture group and to test a lookahead in this part (?!\1)["']`, so it is not so efficient. Writing a simple alternation increases the pattern length and needs to use two captures groups for the two cases but is more efficient:
/\benv:\s*(?:"((?:[^"\\]+|\\[\s\S])*)"|'((?:[^'\\]+|\\[\s\S])*)')/g
(note: if you decided to do that you must check which one of the two capture groups is defined.)
unrolling the loop:
To match the content inside quotes we use (?:[^"\\]+|\\[\s\S])* (for double quotes here) that works but can be improved to reduce the amount of steps needed. To do that we will unroll the loop that consists to avoid the alternation:
[^"\\]*(?:\\[\s\S][^"\\]*)*
finally the whole pattern can be written like this:
/\benv:\s*(?:"([^"\\]*(?:\\[\s\S][^"\\]*)*)"|'([^'\\]*(?:\\[\s\S][^'\\]*)*)')/g

env *('|").*?\1 is what you're looking for
the * means none or more
('|") matches either a single or double quote, and also saves it into a group for backreferencing
.*? is a reluctant greedy match all
\1 will reference the first group, which was either a single or double quote

regex=/env: ?['"]([^'"])+['"]/
answer=str.match(regex)[1]
even better:
regex=/env: ?(['"])([^\1]*)\1/

How to collate sequence \" using ECMAScript regular expressions?

I'm trying to construct a regular expression to treat delimited speech marks (\") as a single character.
The following code compiles fine, but terminates on trying to initialise rgx, throwing the error Abort trap: 6 using libc++.
std::regex rgx("[[.\\\\\".]]");
std::smatch results;
std::string test_str("\\\"");
std::regex_search(test_str, results, rgx);
If I remove the [[. .]], it runs fine, results[0] returning \" as intended, but as said, I'd like for this sequence to be usable as a character class.
Edit: Ok, I realise now that my previous understanding of collated sequences was incorrect, and the reason it wouldn't work is that \\\\\" is not defined as a sequence. So my new question: is it possible to define collated sequences?

So I figured out where I was going wrong and thought I'd leave this here in case anyone stumbles across it.
You can specify a passive group of characters with (?:sequence), allowing quantifiers to be applied as with a character class. Perhaps not exactly what I'd originally asked, but fulfils the same purpose, in my case at least.
To match a string beginning and ending with double quotation marks (including these characters in the results), but allowing delimited quotation marks within the the string, I used the expression
\"(?:[^\"^\\\\]+|(?:\\\\\\\\)+|\\\\\")*\"
which says to grab the as many characters as possible, provided characters are not quotation marks or backslashes, then if this does not match, to firstly attempt to match an even number of backslashes (to allow delimiting of this character), or secondly a delimited quotation mark. This non-capturing group is matched as many times as possible, stopping only when it reaches a \".
I couldn't comment on the efficiency of this, but it definitely works.

Javascript Regex for Javascript Regex and Digits

The title might seem a bit recursive, and indeed it is.
I am working on a Javascript which can highlight/color Javascript code displayed in HTML. Thus, in the Internet Browser, comments will be turned green, definitions (for, if, while, etc.) will be turned a dark blue and italic, numbers will be red, and so on for other elements. However, the coloring is not all that important.
I am trying to figure out two different regular expressions which have started to cause a minor headache.
1. Finding a regular expression using a regular expression
I want to find regular expressions within the script-tags of HTML using a Javascript, such as:
match(/findthis/i);
, where the regex part of course is "/findthis/i".
The rules are as follows:
Finding multiple occurrences (/g) is not important.
It must be on the same line (not /m).
Caseinsensitive (/i).
If a backward slash (ignore character) is followed directly by a forward slash, "/", the forward slash is part of the expression - not an escape character. E.g.: /itdoesntstop\/untilnow:/
Two forward slashes right next to each other (//) is: (A) At the beginning: Not a regex; it's a comment. (B) Later on: First slash is the end of the regex and the second slash is nothing but a character.
Regex continues until the line breaks or end of input (\n|$), or the escape character (second forward slash which complies with rule 4) is encountered. However, also as long as only alphabetic characters are encountered, following the second forward slash, they are considered part of the regex. E.g.: /aregex/allthisispartoftheregex
So far what I've got is this:
'\\/(?:[^\\/\\\\]|\\/\\*)*\\/([a-zA-Z]*)?'
However, it isn't consistent. Any suggestions?
2. Find digits (alphanumeric, floating) using a regular expression
Finding digits on their own is simple. However, finding floating numbers (with multiple periods) and letters including underscore is more of a challenge.
All of the below are considered numbers (a new number starts after each space):
3 3.1 3.1.4 3a 3.A 3.a1 3_.1
The rules:
Finding multiple occurrences (/g) is not important.
It must be on the same line (not /m).
Caseinsensitive (/i).
A number must begin with a digit. However, the number can be preceeded or followed by a non-word (\W) character. E.g.: "=9.9;" where "9.9" is the actual number. "a9" is not a number. A period before the number, ".9", is not considered part of the number and thus the actual number is "9".
Allowed characters: [a-zA-Z0-9_.]
What I've got:
'(^|\\W)\\d([a-zA-Z0-9_.]*?)(?=([^a-zA-Z0-9_.]|$))'
It doesn't work quite the way I want it.

For the first part, I think you are quite close. Here is what I would use (as a regex literal, to avoid all the double escapes):
/\/(?:[^\/\\\n\r]|\\.)+\/([a-z]*)/i
I don't know what you intended with your second alternative after the character class. But here the second alternative is used to consume backslashes and anything that follows them. The last part is important, so that you can recognize the regex ending in something like this: /backslash\\/. And the ? at the end of your regex was redundant. Otherwise this should be fine.
Test it here.
Your second regex is just fine for your specification. There are a few redundant elements though. The main thing you might want to do is capture everything but the possible first character:
/(?:^|\W)(\d[\w.]*)/i
Now the actual number (without the first character) will be in capturing group 1. Note that I removed the ungreediness and the lookahead, because greediness alone does exactly the same.
Test it here.