In javascript you would write something like:
method.apply(this,arguments);
However, how do you translate it to coffeescript?:
method.apply(#, arguments)
Is there a different name for the arguments variable?
Using splats you can use the cleaner coffeescript syntax:
caller: ->
#method arguments...
The above compiles to the following Javascript:
caller: function() {
return this.method.apply(this, arguments);
}
argumentsis available in coffee-script, too. So you can do:
method.apply #, arguments
If you want it to work exactly like javascript, you probably could, but coffeescript has "splats" for what you are probably trying to accomplish. Here's the explanation from coffeescript.org:
gold = silver = rest = "unknown"
awardMedals = (first, second, others...) ->
gold = first
silver = second
rest = others
contenders = [
"Michael Phelps"
"Liu Xiang"
"Yao Ming"
"Allyson Felix"
"Shawn Johnson"
"Roman Sebrle"
"Guo Jingjing"
"Tyson Gay"
"Asafa Powell"
"Usain Bolt"
]
awardMedals contenders...
alert "Gold: " + gold
alert "Silver: " + silver
alert "The Field: " + rest
Related
I'm in a file called event-list.tsx, and I'm trying to create a snippet that writes the following code:
const EventList: FC = () => {
return <div>
</div>;
};
export default EventList;
Thus far, in typescriptreact.json I've written the following snippet setting, which results in awkward-looking code (it puts out const event-list rather than const EventList
"react arrow func component": {
"prefix": "rafce",
"body": [
"const ${TM_FILENAME_BASE}: FC = () => {",
" return <div>",
" ",
" </div>;",
"};",
"",
"export default ${TM_FILENAME_BASE};",
""
]
},
I know how to remove the hyphen from the snippet:
${TM_FILENAME_BASE/-//}
I also figured out how to capitalize the first character:
${TM_FILENAME_BASE/(^.)/${1:/upcase}/}
But I can't figure out how to apply all three of the changes I want. I know the regular expression needed to capitalize every character that comes after a hyphen (a positive lookbehind), but I don't know how to apply it here. There is nothing in the documentation chapter implying the possibility to chain multiple transforms onto each other.
Try the following global regex
${TM_FILENAME_BASE/(.)([^-]*)-?/${1:/upcase}${2}/g}
Find a part before a - and Upcase the first letter, repeat for the whole string
"${TM_FILENAME_BASE/(\\w+)-?/${1:/capitalize}/g}",
(\\w+)-? : You only need one capture group if you use /capitalize.
The hyphens are removed by virtue of matching them (-?) but not including them in the output.
The g flag is necessary to keep matching every (\\w+)-? instance and perform a transform for each.
And since you are reusing an earlier transform you can simplify the whole thing like this:
"react arrow func component": {
"prefix": "rafce",
"body": [
"const ${1:${TM_FILENAME_BASE/(\\w*)-?/${1:/capitalize}/g}}: FC = () => {",
" return <div>",
" ",
" </div>;",
"};",
"",
"export default $1;",
""
]
},
Note that
${1:${TM_FILENAME_BASE/(\\w*)-?/${1:/capitalize}/g}}
stores the result of that transform in variable $1 - which can simply be used later (or earlier) by itself to output the same result!
I am trying to create some kind of a dut_error wrapper. Something that will take some arguments and construct them in a specific way to a dut_error.
I can't use a method to replace the calls to dut_error because to my understanding after check that ... then ... else can only come a dut_error (or dut_errorf). And indeed if I try to do something like:
my_dut_error(arg1: string, arg2: string) is {
dut_error("first argument is ", arg, " and second argument is ", arg2);
};
check that FALSE else my_dut_error("check1", "check2");
I get an error:
*** Error: Unrecognized exp
[Unrecognized expression 'FALSE else my_dut_error("check1", "check2")']
at line x in main.e
check that FALSE else my_dut_error("check1", "check2");
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
So I thought about defining a macro to simply do a textual replace from my wrapper to an actual dut_error:
define <my_dut_error'exp> "my_dut_error(<arg1'name>, <arg2'name>)" as {
dut_error("first argument is ", <arg1'name>, " and second argument is ", <arg2'name>)
};
But got the same error.
Then I read about the preprocessor directive #define so tried:
#define my_dut_error(arg1, arg2) dut_error("first argument is ", arg, " and second argument is ", arg2)
But that just gave a syntax error.
How can I define a pre-compiled textual replacement macro that takes arguments, similar to C?
The reason I want to do that is to achieve some sort of an "interface" to the dut_error so all errors have a consistent structure. This way, different people writing different errors will only pass the arguments necessary by that interface and internally an appropriate message will be created.
not sure i understood what you want to do in the wrapper, but perhaps you can achieve what you want by using the dut_error_struct.
it has set of api, which you can use as hooks (do something when the error is caught) and to query about the specific error.
for example:
extend dut_error_struct {
pre_error() is also {
if source_method_name() == "post_generate" and
source_struct() is a BLUE packet {
out("\nProblem in generation? ", source_location());
// do something for error during generation
};
write() is first {
if get_mesage() ~ "AHB Error..." {
ahb_monitor::increase_errors();
};
};
};
dut_error accepts one parameter, one string. but you can decide of a "separator", that will define two parts to the message.
e.g. - instruct people to write "XXX" in the message, before "first arg" and "second arg".
check that legal else dut_error("ONE thing", "XXX", "another thing");
check that x < 7 else dut_error("failure ", "XXX", "of x not 7 but is ", x);
extend dut_error_struct {
write() is first {
var message_parts := str_split(get_message(), "XXX");
if message_parts.size() == 2 {
out ("First part of message is ", message_parts[0],
"\nand second part of message is ", message_parts[1]
);
};
};
I could get pretty close to what I want using the dut_errorf method combined with a preprocessor directive defining the format string:
#define DUT_FORMAT "first argument is %s and second argument is %s"
check that FALSE else dut_errorf(DUT_FORMAT, "check1", "check2");
but I would still prefer a way that doesn't require this DUT_FORMAT directive and instead uses dut_error_struct or something similar.
One of my test expects an error message text to be one of multiple values. Since getText() returns a promise I cannot use toContain() jasmine matcher. The following would not work since protractor (jasminewd under-the-hood) would not resolve a promise in the second part of the matcher, toContain() in this case:
expect(["Unknown Error", "Connection Error"]).toContain(page.errorMessage.getText());
Question: Is there a way to check if an element is in an array with jasmine+protractor where an element is a promise?
In other words, I'm looking for inverse of toContain() so that the expect() would implicitly resolve the promise passed in.
As a workaround, I can explicitly resolve the promise with then():
page.errorMessage.getText().then(function (text) {
expect(["Unknown Error", "Connection Error"]).toContain(text);
});
I'm not sure if this is the best option. I would also be okay with a solution based on third-parties like jasmine-matchers.
As an example, this kind of assertion exists in Python:
self.assertIn(1, [1, 2, 3, 4])
Looks like you need a custom matcher. Depending on the version of Jasmine you are using:
With Jasmine 1:
this.addMatchers({
toBeIn: function(expected) {
var possibilities = Array.isArray(expected) ? expected : [expected];
return possibilities.indexOf(this.actual) > -1;
}
});
With Jasmine 2:
this.addMatchers({
toBeIn: function(util, customEqualityTesters) {
return {
compare: function(actual, expected) {
var possibilities = Array.isArray(expected) ? expected : [expected];
var passed = possibilities.indexOf(actual) > -1;
return {
pass: passed,
message: 'Expected [' + possibilities.join(', ') + ']' + (passed ? ' not' : '') + ' to contain ' + actual
};
}
};
}
});
You'll have to execute this in the beforeEach section on each of your describe blocks it's going to be used in.
Your expect would look like:
expect(page.errorMessage.getText()).toBeIn(["Unknown Error", "Connection Error"]);
The alternative solution is to use .toMatch() matcher with Regular Expressions and specifically a special character | (called "or"), which allows to match only one entry to succeed:
expect(page.errorMessage.getText()).toMatch(/Unknown Error|Connection Error/);
To me, the work-around that you identified is the best solution. However, we should not forget that this is an asynchronous execution and you might want to consider Jasmine's asynchronous support.
Then, your test will look like the following one:
it('should check item is in array', function(done){ //Note the argument for callback
// do your stuff/prerequisites for the spec here
page.errorMessage.getText().then(function (text) {
expect(["Unknown Error", "Connection Error"]).toContain(text);
done(); // Spec is done!
});
});
Note: If you don't pass this done argument to the spec callback, it is going to run to completion without failures, but no assertions are going to be reported in the execution results for that spec (in other words, that spec will have 0 assertions) and it might lead to confusions.
I am trying to develop a deeper understanding of map/reduce in MongoDB.
I figure the best way to accomplish this is to look at emit's actual implementation. Where can I find it?
Even better would just be a simple implementation of emit(). In the MongoDB documentation, they show a way to troubleshoot emit() by writing your own, but the basic implementation they give is really too basic.
I'd like to understand how the grouping is taking place.
I think the definition you are looking for is located here:
https://github.com/mongodb/mongo/blob/master/src/mongo/db/commands/mr.cpp#L886
There is quite a lot of context needed though to fully understand what is going on. I confess, I do not.
1.Mongo's required JS version is no longer in O.Powell's url, which is dead. I cannot find it.
2.The below code seems to be the snippet of most interest. This cpp function, switchMode, computes the emit function to use. It is currently at;
https://github.com/mongodb/mongo/blob/master/src/mongo/db/commands/mr.cpp#L815
3.I was trying to see if emit has a default to include the _id key, which seems to occur via _mrMap, not shown here. Elsewhere it is initialized to {}, the empty map.
void State::switchMode(bool jsMode) {
_jsMode = jsMode;
if (jsMode) {
// emit function that stays in JS
_scope->setFunction("emit",
"function(key, value) {"
" if (typeof(key) === 'object') {"
" _bailFromJS(key, value);"
" return;"
" }"
" ++_emitCt;"
" var map = _mrMap;"
" var list = map[key];"
" if (!list) {"
" ++_keyCt;"
" list = [];"
" map[key] = list;"
" }"
" else"
" ++_dupCt;"
" list.push(value);"
"}");
_scope->injectNative("_bailFromJS", _bailFromJS, this);
}
else {
// emit now populates C++ map
_scope->injectNative( "emit" , fast_emit, this );
}
}
I have a Map function in MongoDB which I'm later using Reduce on. I use a collection which has a bunch of users in it and users own some channels. However, there are users that do not have any channels and the Map/Reduce function raises an error in my script.
map = Code("function () {"
" if(!this.channels) continue;"
" this.channels.forEach(function(z) {"
" emit(z, 1);"
" });"
"}")
When I use return instead of continue to quit the function it works flawlessly except that I don't want to end the loop. Is there any smart way around this?
Thanks for your advice and better widsom.
If you return from map, it returns only from map for this document. Maps for other documents will be executed regardless of that.
I suggest rewriting your map to this form
function () {
if(this.channels) {
this.channels.forEach(function(z) {
emit(z, 1);
});
}
}
I think, this form is more clear. It will emit something for users that have channels, and skip those that don't have any.