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1. Unary-Pre operators detection fixed.

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2. Unary Minus operator added (now legal, worked before?).
3. GetReference operator (&). For example (a=&b; *a=3;) will set b=3.
4. Operators precedence added (C-like), much more intellectual expressions parsing.
5. Functions redefenition added, use "#name", like "func()(1); #func()(2);".


git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@2950 212acab6-be3b-0410-9dea-997c60f758d6
This commit is contained in:
kichik 2003-09-22 22:56:52 +00:00
parent f82158960d
commit b2574f6b3b
7 changed files with 221 additions and 189 deletions
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33
Contrib/Math/Math.txt
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@ -1,7 +1,5 @@
Math::Script NSIS plugin.
Another huge, undocumented, bug-full, but "might be useful" plugin.
C-like style scripting (operators at least).
Tip1: plugin watches the case of the letters.
Tip2: plugin makes almost no error checks. So YOU should check your script
@ -79,11 +77,15 @@ Operators (some binary, some unary):
>>= <<= -= += /= *= |= &= ^= %= -- ++ >> << && || <= =< >= => != ==
= + - * / % < > & | ^ ~ !
Only some are applicable to float (logic & arithmetic) and string (+ and logic)
of course.
of course.
Additional case: reference/de-reference operators (& and *). & will
give you the reference to argument which should be a variable (NSIS, user, array
item, stack), and * will convert it back to original variable. For example
(a=&b; *a=10) will set b to 10. Expression (*&a) is equal to simple (a).
Script is set of expressions (mathematical in general) delimeted with ';'.
Processing is not mathematicaly right (2+2*2 will give 8, not 6), so use round
brakes (for ex: 2+(2*2) ).
Processing is mathematicaly right (2+2*2 will give 6), operations are performed
in a C like order (precedence).
Flow control:
if-then-else like: #[if-expression, then-expr, else-expr]
@ -159,9 +161,8 @@ Functions:
User-defined functions.
It's very simple. Example:
test(a,b)a+b;
After that test(1,2) will give you 3. If you need more than one expression, use
round brakes:
test(a,b) (a+b);
After that test(1,2) will give you 3.
test2(a,b) (a=a+b; b *= a);
The result of function is always the result of last expression.
As said before it better not to use stack (S) in between function calls.
@ -169,8 +170,8 @@ It will be better to develop variable-safe functions, i.e. functions which will
not corrupt variables. For this you should either push/pop them to stack, or
declare as additional arguments, which will never be used. Example:
test3(a,b,c) (c=10; #{--c > 0, a=sqrt(a*b)}; a)
No matter how many arguments will be passed to function all three vars will be
saved.
No matter how many arguments will be passed to function, the values of all three
vars (a,b,c) will be saved.
Such variable-safe functions could be recursive:
Math::Script /NOUNLOAD 'rec(a) (#[a > 0, rec(a-1), 0]+a);'
Math::Script 'R1 = rec(10)'
@ -184,7 +185,15 @@ at example *b. CAUTION: never use the same variable as function internal referen
variable and external argument variable (for example test4(a,b)). It will surely
fail. Also: if you declared argument as reference - you should never supply
a constant expression to it. It could be either array item (array[1]), NSIS
register R0, any of the user variables (beside the variable with the same name:)
, but never the constant.
register R0, any of the user variables (beside the variable with the same name:),
but never the constant.
Another may-be-useful posibility is to redeclare the function (the usual
declaration at the time when function already defined will simply call that
function). For such task you could use "#name", like "func()(1); #func()(2);".
But beware, function declaration occurs at time of parsing, so it's not possible
to perform flow controlled declaration.
SUCH IS NOT POSSIBLE: "#[a<0, #func()(1), #func()(2)]"
IT WILL SIMPLY DEFINE #func as (2), as the latest variant.
(c) Nik Medved (brainsucker)