Consider this code:
unit uglobals;
{$mode objfpc}{$H+}
interface
const
BORD_WIDTH = 8;
uses
Classes, SysUtils;
implementation
end.
Compilator show me error:
uglobals.pas(8,1) Fatal: Syntax error, "IMPLEMENTATION" expected but "USES" found
Because obviously const section must be after uses section.
Where can I find documentation which gives the order of sections?
I've searched in Google and freepascal.org but I did not find anything about the required order of the sections.
Related
I am using RANSAC to fit a line to my data. The data is 30X2 double, I have used MatLab example to write the code given below, but I am getting an error in my problem. I don't understand the error and unable to resolve it.
The link to Matlab example is
https://se.mathworks.com/help/vision/ref/ransac.html
load linedata
data = [xm,ym];
N = length(xm); % number of data points
sampleSize = 2; % number of points to sample per trial
maxDistance = 2; % max allowable distance for inliers
fitLineFcn = polyfit(xm,ym,1); % fit function using polyfit
evalLineFcn =#(model) sum(ym - polyval(fitLineFcn, xm).^2,2); % distance evaluation function
[modelRANSAC, inlierIdx] = ransac(data,fitLineFcn,evalLineFcn,sampleSize,maxDistance);
The error is as follows
Error using ransac Expected fitFun to be one of these types:
function_handle
Instead its type was double.
Error in ransac>parseInputs (line 202) validateattributes(fitFun,
{'function_handle'}, {'scalar'}, mfilename, 'fitFun');
Error in ransac (line 148) [params, funcs] = parseInputs(data, fitFun,
distFun, sampleSize, ...
Lets read the error message and the documentation, as they tend to have all the information required to solve the issue!
Error using ransac Expected fitFun to be one of these types:
function_handle
Instead its type was double.
Hum, interesting. If you read the docs (which is always the first thing you should do) you see that fitFun is the second input. The error says its double, but it should be function_handle. This is easy to verify, indeed firLineFun is double!
But why? Well, lets read more documentation, right? polyfit says that it returns an array of the coefficient values, not a function_hanlde, so indeed everything the documentation says and the error says is clear about why you get the error.
Now, what do you want to do? It seems that you want to use polyfit as the function to fit with ransac. So we need to make it a function. According to the docs, fitFun has to be of the form fitFun(data), so we just do that, create a function_handle for this;
fitLineFcn=#(data)polyfit(data(:,1),data(:,2),1);
And magic! It works!
Lesson to learn: read the error text you provide, and the documentation1, all the information is there. In fact, I have never used ransac, its just reading the docs that led me to this answer.
1- In fact, programmers tend to reply with the now practically a meme: RTFM often, as it is always the first step on everything programming.
I was trying to figure out what the following Octave code does:
degree = 6;
out = ones(size(X1(:,1)));
for i = 1:degree
for j = 0:i
out(:, end+1) = (X1.^(i-j)).*(X2.^j);
end
end
I wasn't sure what the end+1 meant in Octave until I found the answer for Matlab here:
What is the `end+1` line doing here?
The accepted answer links to the Matlab official documentation which is very clear:
https://www.mathworks.com/help/matlab/ref/end.html
I'm trying to find the documentation for this same keyword in the Octave documentation but I can't seem to find it.
I've searched in the Documentation tab (Octave 5.1.0), using the function index and the search tab to no avail although I see it used in several documentation pages.
The Octave documentation, which seems to be categorized more by usage than keyword, on Index Expressions is also as explicit:
In index expressions the keyword end automatically refers to the last entry for a particular dimension. This magic index can also be used in ranges and typically eliminates the needs to call size or length to gather array bounds before indexing.
Try help end in Octave. That will give you what you're looking for.
In Octave and Matlab, there are two help-finding functions, help and doc. (doc is what pops up the GUI documentation browser.) And they will give you different results for the same topics! So always try both when you're looking for something.
And there's nothin' wrong with looking through the Matlab doco and Stack Overflow answers for this. Octave is pretty compatible with Matlab, so anything you find there for basic language functionality (except for strings, tables, and datetimes) will apply to Octave as well.
I'm using re-frame with spec to validate app-db, much like in the todomvc example.
When a user makes an invalid entry, I'm using s/explain-data (in a re-frame interceptor) to return a problems map naming the :predicate which caused validation failure. This predicate is a symbol like project.db/validation-function.
My validation function has metadata which is accessible from the repl using:
(meta #'project.db/validation-function)
The function definition (in the project.db namespace) looks like this:
(defn validation-function
"docstring..."
{:error-message "error message"}
[param]
(function-body...)
The problem is I can't work out how to retrieve the metadata dynamically (working in project.events namespace), for example:
(let [explain-data (s/explain-data spec db)
pred (->> (:cljs.spec.alpha/problems explain-data) first :pred)
msg (what-goes-here? pred)]
msg)
I've tried the following things in place of what-goes-here?:
symbol? gives true
str gives "project.db/validation-function"
meta gives nil
var gives a compile-time error "Unable to resolve var: p1__46744# in this context"
I think the problem is that I'm getting a symbol, but I need the var it refers to, which is where the metadata lives.
I've tried using a macro, but don't really know what I'm doing. This is the closest discussion I could find, but I couldn't work it out.
Help!
In general, you can't do this because vars are not reified in ClojureScript.
From https://clojurescript.org/about/differences#_special_forms :
var notes
Vars are not reified at runtime. When the compiler encounters the var special form it emits a Var instance reflecting compile time metadata. (This satisfies many common static use cases.)
At the REPL, when you evaluate
(meta #'project.db/validation-function)
this is the same as
(meta (var project.db/validation-function))
and when (var project.db/validation-function) is compiled, JavaScript code is emitted to create a cljs.core/Var instance that contains, among other things, the data that you can obtain using meta. If you are curious, the relevant analyzer and compiler code is instructive.
So, if (var project.db/validation-function) (or the reader equivalent #'project.db/validation-function) doesn't exist anywhere in your source code (or indirectly via the use of something like ns-publics) this data won't be available at runtime.
The omission of var reification is a good thing when optimizing for code size. If you enable the :repl-verbose REPL option, you will see that the expression (var project.db/validation-function) emits a significant amount of JavaScript code.
When working with defs at the REPL, the compiler carries sufficient analysis metadata, and things are done—like having evaluations of def forms return the var rather than the value—in the name of constructing an illusion that you are working with reified Clojure vars. But this illusion intentionally evaporates when producing code for production delivery, preserving only essential runtime behavior.
edit: sorry I didn't see that var didn't work for you. Still working on it...
You need to surround the symbol project.db/validation-function with var. This will resolve the symbol to a var.
So what-goes-here? should be
(defn what-goes-here? [pred]
(var pred))
I implementing basic library to deal with Windows Firewall API.
I faced with strange result with INetFwPolicy2::ExcludedInterfaces property.
I set excluded interface via Firewall.cpl and when read property I got array of some guids. I am not sure from where this GUID come. It is not Interface GUID. I select all interfaces from Win32_NetworkAdapter and there no such GUID.
Also when I try assign this value back I got invalid argument or not found errors.
This code based on msdn example written on on VBS, but it really does not matter I have same error on C. Original example did not works either.
Const NET_FW_PROFILE2_PRIVATE = 2
Set fwPolicy2 = CreateObject("HNetCfg.FwPolicy2")
CurrentProfiles = fwPolicy2.CurrentProfileTypes
if ( CurrentProfiles AND NET_FW_PROFILE2_PRIVATE ) then
InterfaceArray = fwPolicy2.ExcludedInterfaces(NET_FW_PROFILE2_PRIVATE)
if (IsEmpty(InterfaceArray)) then
WScript.Echo( "InterfaceArray is Empty" )
else
WScript.Echo( Join(InterfaceArray) )
end if
fwPolicy2.ExcludedInterfaces(NET_FW_PROFILE2_PRIVATE) = InterfaceArray
end if
Check your csproj file xml in your executing assembly (not necessarily the assembly that uses windows-firewall-api if it is referenced). For each configuration there is a <PropertyGroup> tag, and each should have a child tag <Prefer32Bit>false</Prefer32Bit> (or at least the one that you compile with).
I recently found out that you can get Octave to warn when you are using features not compatible with Matlab. Due to working with others this feature is appealing.
warning ('on', 'Octave:matlab-incompatible')
However when I use it in even simple scripts
warning ('on', 'Octave:matlab-incompatible');
x = 5;
plot(x);
I get many warning due to the implementation of plot using non-Matlab compatible features. For example
warning: potential Matlab compatibility problem: ! used as operator near line 215 offile /usr/share/octave/3.8.1/m/plot/draw/plot.m
Is there a way to turn off these warnings? I don't care if plot is implemented using non-Matlab features because when I use Matlab its implementation will be fine.
No that is not possible which makes the Octave:matlab-incompatible almost useless. Also, that warning is only printed for syntax so you can still use Octave only functions (such as center or sumsq) without any problem.
I recommend you use a text editor that has separate Matlab and Octave syntax highlight (such as gedit) and avoid things that don't get highlighted.
Here's how it's done in Matlab, which looks to be similar to the Octave case:
warning('on', 'Octave:matlab-incompatible'); % Your Octave warning
x = 5;
WarnState = warning('off', 'Offending_MSGID'); % You'll need to get the specific ID
plot(x);
warning(WarnState); % Restore
Yes, it's a bit clumsy. There's no way to specify that a warning is not enabled within a particular file that I know of.
One thing that can happen is that the code an be interrupted by the user or an error before the warning state is restored. In this case, Your system now is in an unknown warning state. One way to avoid this is to use onCleanup. This function is called when a function exits, even if it exits due to an error. You might rewrite the above as:
warning('on', 'Octave:matlab-incompatible'); % Your Octave warning
x = 5;
WarnState = warning('off', 'Offending_MSGID'); % You'll need to get the specific ID
C = onCleanup(#()warning(WarnState));
plot(x);
...
Note that onCleanup won't be called until the function exits so the warning state won't be restored until then. You should be able to add a warning(WarnState); line to manually restore before if you want. Just be sure that whatever function onCleanup is calling can never return an error itself.