Best way to for F-Script validation?
Vyacheslav Artemev
have F-Script editor in my app. Question is what are the best way to
validate F-Script code without executing it?
Jonathan Mitchell
I use the following.
Basically we build a block from our source and trap any exceptions that result.
The only small issue is the need to access framework non public API.
Regards
Jonathan Mitchell
Mugginsoft LLP
================================================
KosmicTask - the Integrated Scripting Environment for OS X.
http://www.mugginsoft.com/KosmicTask
================================================
#import <FScript/FScript.h>
#import "BlockStackElem.h" // on user search path
- (BOOL)build {
NSString *resultString = @"";
// get script source
NSString *source = [self scriptSourceWithError:YES];
if (!source) return NO;
@try {
// make a block. raises on compilation or syntax error
//
// http://www.fscript.org/documentation/EmbeddingFScriptIntoCocoa/index.htm
//
FSBlock *block = [source asBlock];
(void)block;
}
@catch (NSException* e) {
NSDictionary *userInfo = [e userInfo];
// the exception reason has the error string but no line number info
// (this could perhaps be calculated from the character indicies in
// BlockStackElem)
NSArray *blockStack = [userInfo objectForKey:@"FScriptBlockStack"];
// block stack elem is not part of the public API
// hence we import it separately.
// FSInterpreterResult does supply all error info
// but it is returned only as result of execution
BlockStackElem *blockStackElem = [blockStack objectAtIndex:0];
// report error
self.error = [NSString stringWithFormat:@"%@", [blockStackElem errorStr]];
// get error range
NSUInteger firstCharIndex = [blockStackElem firstCharIndex];
NSUInteger lastCharIndex = [blockStackElem lastCharIndex];
NSRange range = NSMakeRange(firstCharIndex, lastCharIndex - firstCharIndex);
self.errorInfo = [NSMutableDictionary dictionaryWithCapacity:2];
[self.errorInfo setObject:NSStringFromRange(range) forKey:MGSRangeErrorKey];
[self.errorInfo setObject:self.error forKey:NSLocalizedFailureReasonErrorKey]; // required
}
return [self processBuildResult:resultString];
}
Philippe Mougin
wrote:
>
> > Currently i develop Cocoa application with embedded F-Script. So, i
> > have F-Script editor in my app. Question is what are the best way to
> > validate F-Script code without executing it?
>
> I use the following.
> Basically we build a block from our source and trap any exceptions that result.
> The only small issue is the need to access framework non public API.
>
> Regards
>
> Jonathan Mitchell
> Mugginsoft LLP
>
> ================================================
>
> #import <FScript/FScript.h>
> #import "BlockStackElem.h" // on user search path
>
> - (BOOL)build {
>
> NSString *resultString = @"";
>
> // get script source
> NSString *source = [self scriptSourceWithError:YES];
> if (!source) return NO;
>
> @try {
>
> // make a block. raises on compilation or syntax error
> //
> FSBlock *block = [source asBlock];
> (void)block;
> }
> @catch (NSException* e) {
> NSDictionary *userInfo = [e userInfo];
>
> // the exception reason has the error string but no line number info
> // (this could perhaps be calculated from the character indicies in
> // BlockStackElem)
> NSArray *blockStack = [userInfo objectForKey:@"FScriptBlockStack"];
>
> // block stack elem is not part of the public API
> // hence we import it separately.
> // FSInterpreterResult does supply all error info
> // but it is returned only as result of execution
> BlockStackElem *blockStackElem = [blockStack objectAtIndex:0];
>
> // report error
> self.error = [NSString stringWithFormat:@"%@", [blockStackElem errorStr]];
>
> // get error range
> NSUInteger firstCharIndex = [blockStackElem firstCharIndex];
> NSUInteger lastCharIndex = [blockStackElem lastCharIndex];
>
> NSRange range = NSMakeRange(firstCharIndex, lastCharIndex - firstCharIndex);
> self.errorInfo = [NSMutableDictionary dictionaryWithCapacity:2];
> [self.errorInfo setObject:NSStringFromRange(range) forKey:MGSRangeErrorKey];
> [self.errorInfo setObject:self.error forKey:NSLocalizedFailureReasonErrorKey]; // required
> }
>
> return [self processBuildResult:resultString];
> }
An alternative, that avoid touching private APIs, is to use the method
"asBlockOnError:" defined in the FSNSString category (or the method
"blockFromString:onError:" in FSSystem).
For example:
[source asBlockOnError:[@"[:msg :start :end | {msg, start, end}]"
asBlock]];
This will either return an FSBlock instance (if there is no syntax
error) or an array with error information (if there is a syntax
error).
A second alternative is to use FSInterpreter's execute method after
patching the source code you want to validate in a way that will
prevent it to execute, as shown here:
FSInterpreterResult *result = [myInterpreter execute:[NSString
stringWithFormat:@"[%@]", source]];
If you then use the error range provided by FSInterpreterResult,
remember to decrement the location by one.
Philippe
Vyacheslav Artemev
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