All the primitives in the Cog have error codes. Pharo does not write it explicitly for each primitive, but Pharo could. Knowing why a primitive failed is very useful. The Cog support over 400 primitives. Do you want to copy that comment 400 times ? I don't think so. What if one wants to update that comment, one would need to update all the 400 comments ? That's insane and very hard to maintain.
It would be nice to update the comment of Object class>>#whatIsAPrimitive with a paragraph on error code instead, such as the one you wrote. On Sun, Jun 26, 2016 at 8:00 PM, stepharo <steph...@free.fr> wrote: > So could we have a nice method comments that I can add to all the > primitive using this ec? > > Proposal: > https://pharo.fogbugz.com/f/cases/18618/Better-additional-comment-for-primitive-79-error-ec-usage > > "ec is a special temporary variable that holds an error code. In the > VM primitive, failure is indicated by a variable called primFailCode being > non-zero. On activating a method with a failing primitive, if the index is > in bounds of the primitiveFailCodes array in the VMspecialObjectsArray then > the failure code substitutes the symbol in the primitiveFailCodes array, > otherwise it supplies the integer value." > > Because what I like the most in smalltalk besides live coding is comments. > > Stef > > > > > Le 22/6/16 à 17:25, Clément Bera a écrit : > > It's a special case added a couple year ago to figure out why a primitive > fail. > > It's a special temporary variable that holds an error code. The special > object array defines a list of error code that the VM can use to explain to > the programmer why the primitive failed, which are currently symbols. > > > > On Wed, Jun 22, 2016 at 4:22 PM, Max Leske <maxle...@gmail.com> wrote: > >> >> > On 22 Jun 2016, at 15:59, stepharo < <steph...@free.fr>steph...@free.fr> >> wrote: >> > >> > Hi >> > >> > I want to explain where ec is coming. >> > >> > I thought that the arguments of pragmas could only be literal and when >> I see ec it looks like a variable set by the VM >> > >> > >> > newMethod: numberOfBytes header: headerWord >> > "Primitive. Answer an instance of me. The number of literals (and >> other >> > information) is specified by the headerWord (see my class comment). >> > The first argument specifies the number of fields for bytecodes in >> the >> > method. Fail if either argument is not a SmallInteger, or if >> numberOfBytes >> > is negative, or if memory is low. Once the header of a method is >> set by >> > this primitive, it cannot be changed to change the number of >> literals. >> > Essential. See Object documentation whatIsAPrimitive." >> > >> > <primitive: 79 error: ec> >> > ec == #'insufficient object memory' ifTrue: >> > [^self handleFailingNewMethod: numberOfBytes header: headerWord]. >> > ^self primitiveFailed >> > >> > >> > Stef >> > >> > >> >> That is correct. It’s still a literal though. >> > > >
