In an ancient PowerBasic file, I found this in the code:
%AppendRec= 1% '^a Write/Append Btrieve record to named file
%PrtBar= 2% '^b Print a Bar Code
My question deals with the numbers after the = sign. I assume the trailing % has a meaning, but I can't figure out what that meaning is.
I know that in QB, % denotes an Integer type but that normally leads the variable as shown at the beginning of the code lines. The trailing % has me confused.
It is used to specify the type of the constant, so you don't have e.g. "1" evaluate to a float and then have to be converted to an int.
This page shows you the defaults that PB uses if you don't explicitly specify the type of constants.
Like Charles said it defines the type as int. Prefixing it with % like the variable on the left is defining a numeric equate/constant. The page link is old now though and their new help is at PowerBasicHelp
Look for Numeric Equates and Data Types.
Related
I am looping over a set of scalars which contain quarterly sif values. I would like to convert them to hrf format and keep them stored in scalars.
However, I found that format %tq only accepts variables. Hence, the only workaround seems to i) convert the scalar to a variable ii) apply format %tq iii) convert the variable to a scalar.
Is there a more elegant and faster way to do this? (I am using Stata MP 15.1.)
You can have string scalars, so you can do this. I can't see why it would be useful, but that could be failure of imagination; you could enlighten us on why you want this.
. scalar foo = yq(2018, 4)
. scalar foo = string(scalar(foo), "%tq")
. scalar list
foo = 2018q4
What is quite different for scalars is that there is no sense whatsoever in which a display format is attached to or associated with a scalar. You can hold a numeric date or a string date in a scalar, but those are the only choices. You can't have a numeric value with a format on the side that Stata will use for display when suitable. You found that out when you attempted to format a scalar.
Goodness knows whether this is faster (than what?) or more elegant (who decides?). The major difference is that a variable manifestly can contain many dates and a changed format made just once with format can apply to them consistently, whereas changing how you show a bunch of scalars requires a loop every time you do it so far as I can see. Further, it follows from above that you might need to keep two sets of scalars, one numeric for calculation and one string for display.
I've used date constants and typically found that either I use them directly (subtracting 2000 as base doesn't requiring putting it into anything) or I use local macros to hold them. But I can't see anything wrong with using scalars, except possibly indirection.
I have to name methods based on the index number of some external documentation:
def 51_bic
end
This is wrong, as shown by the color with the syntax highlighting. And also the code fails with trailing `_' in number (SyntaxError).
Using bic_51 works just fine. But why is that? What's the nature of the fact that I can't use integer + underscore + string? My understanding is that everything after a def is just a method name as a string.
Identifiers can have numbers in them, but can't start with a number. This is how it is in most programming languages (that I heard of).
What's the nature of the problem that I can't use integer + underscore + string?
Because if you allow identifiers to start with a number, you must then mandate that they contain a letter after (to differentiate them from numbers). Now, food for thought. Imagine you can start identifiers with numbers. Which of these are method calls, local variables and which are number literals?
0xa0 + 0b10_100 + 3_456
How can I use parameters in format descriptor in Fortran90?
I want to make a matrix, say square(n*n), but I want to make it general. So, I declared a parameter like this: integer,parameter::n=3 (say n is 3 here)
Then after inputting the elements of the matrix in a do/implied do loop, I want to write it with the format function as follows:
format(ni5)
But it gives the error: Unexpected element 'N' in format string
Any simple way to solve this??
Little-known fact: format specifiers can be constructed at runtime as a character string. This means that you can programmatically define the format specifier and pass it to the write statement.
CHARACTER(len=30) fm
INTEGER :: i
i = 3
WRITE(fm,'(a,i1,a)')"(",i,"i5)"
WRITE(*,fm)1,2,3
In the above, we are generating the actual format specifier with the number of integers that you need to print for the given situation (i), then using that string as the format of the second write statement.
I very rarely see people use this trick, and its possible that it is not defined in the actual standard, but it does work in gfortran.
I would like to implement a small subset of siri/cortana like features in command line.
For e.g.
$ What is the sum of 100 and 1000
> Response: 1100
$ What is the product of 10 and 12
> Response: 120
The questions are predefined regular expressions. It needs to call the matching function in ruby.
Pattern: What is the sum of (\d)+ and (\d)+
Ruby method to call: sum(a,b)
Any pointers/suggestion is appreciated.
That sounds exactly like cucumber, maybe take a look and see if you can just use their classes to hack something together :) ?
You could do something like the following:
question = gets.chomp
/\A.*(sum |product |quotient |difference )\D+([0-9]+)\D+([0-9]+).*\z/.match question
send($1, $2.to_i, $3.to_i)
Quick explanation for anyone that may be new to matching in Ruby:
This gets a line of input from the command line and scans it for a function name (i.e. sum, product, etc) followed by a space and potentially some non-digit characters. Then, it looks for a first number (similarly followed by a space and 0 or more non-digit characters) and a second number followed by nothing or anything. The parentheses determine what gets assigned to the variables preceded by a $, i.e. the substring that matches the contents of the first set of parentheses gets assigned to $1.
Next, it calls the method whose name is the value of $1 with the arguments (casted to integers) found in $2 and $3.
Obviously, this isn't generalized at all--you're putting the method names in the regex, and it's taking a fixed number of arguments--but it'll hopefully be useful for getting you on the right track.
I just got a bunch of legacy VB6 (!) code dumped on me and I keep seeing functions declared with an ampersand at the end of the name, for example, Private Declare Function ShellExecute& . . ..
I've been unable to find an answer to the significance of this, nor have I been able to detect any pattern in use or signature of the functions that have been named thusly.
Anyone know if those trailing ampersands mean anything to the compiler, or at least if there's some convention that I'm missing? So far, I'm writing it off as a strange programmer, but I'd like to know for sure if there's any meaning behind it.
It means that the function returns a Long (i.e. 32-bit integer) value.
It is equivalent to
Declare Function ShellExecute(...) As Long
The full list of suffixes is as follows:
Integer %
Long &
Single !
Double #
Currency #
String $
As Philip Sheard has said it is an indentifier type for a Long. They are still present in .Net, see this MSDN link and this VB6 article
From the second article:
The rules for forming a valid VB variable name are as follows:
(1) The first character must be a letter A through Z (uppercase or
lowercase letters may be used). Succeeding characters can be letters,
digits, or the underscore (_) character (no spaces or other characters
allowed).
(2) The final character can be a "type-declaration character". Only
some of the variable types can use them, as shown below:
Data Type Type Declaration Character
String $
Integer %
Long &
Single !
Double #
Currency #
Use of type-declaration
characters in VB is not encouraged; the modern style is to use the
"As" clause in a data declaration statement.