May 2017 - Pharo-users - lists.pharo.org

Re: [Pharo-users] How to use uFFI with String

by Stephane Ducasse

Did you read the UFFI chapter? https://ci.inria.fr/pharo-contribution/view/Books/job/PharoBookWorkInProgre… https://ci.inria.fr/pharo-contribution/view/Books/job/PharoBookWorkInProgre… I'm turning it into a booklet but I will not write it because I'm bad in FFI Now if you have corrections, suggestions, please do some pull requests https://github.com/SquareBracketAssociates/Booklet-uFFI Stef On Mon, May 22, 2017 at 10:42 PM, horrido <horrido.hobbies(a)gmail.com> wrote: > There is shockingly very little documentation on how to use uFFI. In > particular, I have the following situation... > > A shared C lib has the following function: > > void get_machine(char *machine) { > uname(&uname_s); > strcpy(machine, uname_s.machine); > } > > It copies the content of a string value into the buffer passed to it (char > *machine). > > I want to call this function from Pharo, thus: > > buffer := String new: 64. > self ffiCall: #( void get_machine(String buffer) ). > > The buffer never receives the string value (it just contains the 64 > initiialized spaces). > > Clearly, I'm misunderstanding the proper mechanism for doing this. > > [There are other functions in the shared C lib that work fine, such as: > > uint get_uptime() { > sysinfo(&info); > return info.uptime; > } > > Returning integers or floats is no problem. But passing arguments by > reference seems to be verboten.] > > > > -- > View this message in context: http://forum.world.st/How-to- > use-uFFI-with-String-tp4947890.html > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. > >

May 25, 2017

Re: [Pharo-users] How to query a JSON

by Stephane Ducasse

mark what you can also do is to generate the classes from the json we did that for certain libraries. Stef On Wed, May 24, 2017 at 4:20 PM, Marc Hanisch via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > > > ---------- Forwarded message ---------- > From: Marc Hanisch <marc.hanisch(a)googlemail.com> > To: Any question about pharo is welcome <pharo-users(a)lists.pharo.org> > Cc: > Bcc: > Date: Wed, 24 May 2017 16:20:14 +0200 > Subject: How to query a JSON > Hello, > > is there a way to query a JSON with a path (JSONPath or some custom > format)? > > I want to query an API and collect the JSON responses, which I need to > iterate over to extract some data. Modelling the JSON structure as classes > would be too much overhead, I think. I just want to collect some values... > > Thanks in advance, > Marc > >

May 25, 2017

Re: [Pharo-users] How to query a JSON

by Sven Van Caekenberghe

> On 24 May 2017, at 17:09, Marc Hanisch <marc.hanisch(a)googlemail.com> wrote: > > Hello Sven, > > Thanks for that hint! It looks like exactly what I need âºï¸ Here is a quick example using the new JSON Feed format (https://jsonfeed.org) json := ZnClient new systemPolicy; url: 'https://daringfireball.net/feeds/json'; accept: ZnMimeType applicationJson; contentReader: [ :entity | NeoJSONObject fromString: entity contents ]; get. json items collect: #title. json items collect: [ :each | each title -> each url ]. Note how you can just pretend that the objects understand #items, #title or #url. > Best regards, > Marc > > Am 24.05.2017 16:38 schrieb "Sven Van Caekenberghe" <sven(a)stfx.eu>: > Marc, > > > On 24 May 2017, at 16:20, Marc Hanisch via Pharo-users <pharo-users(a)lists.pharo.org> wrote: > > > Hello, > > > > is there a way to query a JSON with a path (JSONPath or some custom format)? > > > > I want to query an API and collect the JSON responses, which I need to iterate over to extract some data. Modelling the JSON structure as classes would be too much overhead, I think. I just want to collect some values... > > > > Thanks in advance, > > Marc > > Normally, when you use the NeoJSON package and you don't do any mapping, you get Dictionaries and Arrays back. > > There is however also something called NeoJSONObject, a Dictionary subclass that has some API that is quite fluent and that does include path style access. > > To get started, use NeoJSONObject class>>#fromString: as parser. > > Here is the class comment: > > === > I am NeoJSONObject. > I am a Dictionary. > > I behave more like a JavaScript object. I return nil for missing keys. I allow any property to be read or set by using a normal accessor message. > > The following are equivalent: > > self foo. > self at: #foo. > > As are the following > > self foo: 1. > self at: #foo put: 1. > > Except that in the first case, self is returned. > > I can optionally be used by NeoJSONReader as mapClass (see #mapClass:). > > For output, I act just like my superclass (it is thus not necessary to do any conversions). > > Example: > > NeoJSONObject fromString: '{"foo":1,"bar":-2}'. > NeoJSONObject new foo: 1; bar: -2. > { #x -> 100. #y -> 200 } as: NeoJSONObject. > (NeoJSONObject new data: (NeoJSONObject new id: #sensor1; value: 37.5)) asString. > > I use JSON as my printed representation. To convert me to JSON, use #printString or #asString. > > Additionally, I support path access for nested instances of me, using #atPath: and #atPath:put: > > The first is special because it returns nil as soon as a key is missing. The second is special because it creates extra levels (instances of me) as needed to follow the path of keys. > > NeoJSONObject new atPath: #(one two three) put: 42; yourself. > NeoJSONObject new atPath: #(one two three) put: 42; atPath: #(one two three). > === > > HTH, > > Sven > >

May 24, 2017

Re: [Pharo-users] How to use uFFI with String

by horrido

Let's say you have a shared C library (called testlib.so) with the following function signature: void func1(int *buf); How would you use uFFI to call this function? How would you complete the following code fragment: self ffiCall: #( void func1(??? buf) ) module: 'testlib.so'. where buf should hold whatever integer value func1 puts into it. Maybe buf needs to be prepared somehow before the ffiCall? horrido wrote > Je comprends enfin... > > I accidentally came across a StackOverflow answer that suggested the > String object is immutable. That makes perfect sense, as I know the C > function is actually /* > trying */ > to write to the buffer. > > That gave me the idea to use a ByteArray instead. Now, everything works! > > horrido wrote >> There is shockingly very little documentation on how to use uFFI. In >> particular, I have the following situation... >> >> A shared C lib has the following function: >> >> void get_machine(char *machine) { >> uname(&uname_s); >> strcpy(machine, uname_s.machine); >> } >> >> It copies the content of a string value into the buffer passed to it >> (char *machine). >> >> I want to call this function from Pharo, thus: >> >> buffer := String new: 64. >> self ffiCall: #( void get_machine(String buffer) ). >> >> The buffer never receives the string value (it just contains the 64 >> initiialized spaces). >> >> Clearly, I'm misunderstanding the proper mechanism for doing this. >> >> [There are other functions in the shared C lib that work fine, such as: >> >> uint get_uptime() { >> sysinfo(&info); >> return info.uptime; >> } >> >> Returning integers or floats is no problem. But passing arguments by >> reference seems to be verboten.] -- View this message in context: http://forum.world.st/How-to-use-uFFI-with-String-tp4947890p4948184.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

May 24, 2017

Re: [Pharo-users] How to query a JSON

by Marc Hanisch

Hello Sven, Thanks for that hint! It looks like exactly what I need âºï¸ Best regards, Marc Am 24.05.2017 16:38 schrieb "Sven Van Caekenberghe" <sven(a)stfx.eu>: > Marc, > > > On 24 May 2017, at 16:20, Marc Hanisch via Pharo-users < > pharo-users(a)lists.pharo.org> wrote: > > > Hello, > > > > is there a way to query a JSON with a path (JSONPath or some custom > format)? > > > > I want to query an API and collect the JSON responses, which I need to > iterate over to extract some data. Modelling the JSON structure as classes > would be too much overhead, I think. I just want to collect some values... > > > > Thanks in advance, > > Marc > > Normally, when you use the NeoJSON package and you don't do any mapping, > you get Dictionaries and Arrays back. > > There is however also something called NeoJSONObject, a Dictionary > subclass that has some API that is quite fluent and that does include path > style access. > > To get started, use NeoJSONObject class>>#fromString: as parser. > > Here is the class comment: > > === > I am NeoJSONObject. > I am a Dictionary. > > I behave more like a JavaScript object. I return nil for missing keys. I > allow any property to be read or set by using a normal accessor message. > > The following are equivalent: > > self foo. > self at: #foo. > > As are the following > > self foo: 1. > self at: #foo put: 1. > > Except that in the first case, self is returned. > > I can optionally be used by NeoJSONReader as mapClass (see #mapClass:). > > For output, I act just like my superclass (it is thus not necessary to do > any conversions). > > Example: > > NeoJSONObject fromString: '{"foo":1,"bar":-2}'. > NeoJSONObject new foo: 1; bar: -2. > { #x -> 100. #y -> 200 } as: NeoJSONObject. > (NeoJSONObject new data: (NeoJSONObject new id: #sensor1; value: > 37.5)) asString. > > I use JSON as my printed representation. To convert me to JSON, use > #printString or #asString. > > Additionally, I support path access for nested instances of me, using > #atPath: and #atPath:put: > > The first is special because it returns nil as soon as a key is missing. > The second is special because it creates extra levels (instances of me) as > needed to follow the path of keys. > > NeoJSONObject new atPath: #(one two three) put: 42; yourself. > NeoJSONObject new atPath: #(one two three) put: 42; atPath: #(one > two three). > === > > HTH, > > Sven > > >

May 24, 2017

Re: [Pharo-users] How to query a JSON

by Sven Van Caekenberghe

Marc, > On 24 May 2017, at 16:20, Marc Hanisch via Pharo-users <pharo-users(a)lists.pharo.org> wrote: > Hello, > > is there a way to query a JSON with a path (JSONPath or some custom format)? > > I want to query an API and collect the JSON responses, which I need to iterate over to extract some data. Modelling the JSON structure as classes would be too much overhead, I think. I just want to collect some values... > > Thanks in advance, > Marc Normally, when you use the NeoJSON package and you don't do any mapping, you get Dictionaries and Arrays back. There is however also something called NeoJSONObject, a Dictionary subclass that has some API that is quite fluent and that does include path style access. To get started, use NeoJSONObject class>>#fromString: as parser. Here is the class comment: === I am NeoJSONObject. I am a Dictionary. I behave more like a JavaScript object. I return nil for missing keys. I allow any property to be read or set by using a normal accessor message. The following are equivalent: self foo. self at: #foo. As are the following self foo: 1. self at: #foo put: 1. Except that in the first case, self is returned. I can optionally be used by NeoJSONReader as mapClass (see #mapClass:). For output, I act just like my superclass (it is thus not necessary to do any conversions). Example: NeoJSONObject fromString: '{"foo":1,"bar":-2}'. NeoJSONObject new foo: 1; bar: -2. { #x -> 100. #y -> 200 } as: NeoJSONObject. (NeoJSONObject new data: (NeoJSONObject new id: #sensor1; value: 37.5)) asString. I use JSON as my printed representation. To convert me to JSON, use #printString or #asString. Additionally, I support path access for nested instances of me, using #atPath: and #atPath:put: The first is special because it returns nil as soon as a key is missing. The second is special because it creates extra levels (instances of me) as needed to follow the path of keys. NeoJSONObject new atPath: #(one two three) put: 42; yourself. NeoJSONObject new atPath: #(one two three) put: 42; atPath: #(one two three). === HTH, Sven

May 24, 2017

How to query a JSON

by Marc Hanisch

Hello, is there a way to query a JSON with a path (JSONPath or some custom format)? I want to query an API and collect the JSON responses, which I need to iterate over to extract some data. Modelling the JSON structure as classes would be too much overhead, I think. I just want to collect some values... Thanks in advance, Marc

May 24, 2017

Re: [Pharo-users] How to add a contextual menu to a Spec

by Sven Van Caekenberghe

Hi Hartmut, Thanks for the reply. Like I said in my previous post 'I like to stay within Spec as much as possible', it got it working fine now. Sven > On 24 May 2017, at 12:03, Hartmut Krasemann <Hartmut.Krasemann(a)t-online.de> wrote: > > Hi Sven, >> Subject: [Pharo-users] How to add a contextual menu to a Spec >> ListModel >> Message-ID: >> <5BBF6BCB-2C95-4948-932C-D14F71C0B3D9(a)stfx.eu> >> >> Content-Type: text/plain; charset=us-ascii >> >> Hi, >> >> I am struggle a bit in find the right way to add a contextual menu to a Spec ListModel. >> >> Consider: >> >> ListModel new >> title: 'List Example'; >> items: Smalltalk allClasses; >> openWithSpec. >> >> I would like to add a right-click contextual menu to the list, with for example a 'Browse' action. I can't find such a simple example. I know there is a #menu: option, I can see some usages in my image, but they seem to do different things. What would be the recommended approach ? >> >> ListModel new >> title: 'List Example'; >> items: Smalltalk allClasses; >> "menu: [ ];" >> openWithSpec. >> >> Thanks, >> >> Sven >> >> PS: Probably the reference to the #selectedItem of the ListModel for the action is hard to write in a one-liner, that is not a requirement. >> >> > I found the following to work for ListModel and MultiColumnList, > e.g to add #inspect as a list item pop up : > > menu: [ :m | self listMenu: m ] . > > listMenu: m > | item | > item := m add: #inspect target: self selectedItem selector: #inspect . > item enablementSelector: [ self selectedItem isNotNil ] . > ^m > > Hartmut > -- > Hartmut Krasemann > KÃ¶nigsberger Str. 41 c > D 22869 Schenefeld > Tel. 040.8307097 > Mobil 0171.6451283 > Krasemann(a)acm.org

May 24, 2017

Re: [Pharo-users] How to add a contextual menu to a Spec ListModel

by Sven Van Caekenberghe

> On 24 May 2017, at 11:58, Nicolai Hess <nicolaihess(a)gmail.com> wrote: > > > > 2017-05-24 11:25 GMT+02:00 Sven Van Caekenberghe <sven(a)stfx.eu>: > Hi, > > I am struggle a bit in find the right way to add a contextual menu to a Spec ListModel. > > Consider: > > ListModel new > title: 'List Example'; > items: Smalltalk allClasses; > openWithSpec. > > I would like to add a right-click contextual menu to the list, with for example a 'Browse' action. I can't find such a simple example. I know there is a #menu: option, I can see some usages in my image, but they seem to do different things. What would be the recommended approach ? > > ListModel new > title: 'List Example'; > items: Smalltalk allClasses; > "menu: [ ];" > openWithSpec. > > Thanks, > > Sven > > PS: Probably the reference to the #selectedItem of the ListModel for the action is hard to write in a one-liner, that is not a requirement. > > > It is a problem or at least confusing that the menu: method does not uses a MenuModel, but a Morphic menu. > > If you don't want to touch a Morphic class from within the ListModel, > you can do it like it is done in some tools, just ignore the MenuMorph and instantiate a new MenuModel and call > buildWithSpecAsPopup. > > Or add your menu items to the menu argument: > > l:=ListModel new. > l > title: 'List Example'; > items: Smalltalk allClasses; > menu: [:menu :shifted | > (menu > add: 'Browse' > target: l selectedItem > selector: #browse) > isEnabled: l selectedItem notNil. > "return the menu object" > menu > ]; > openWithSpec. Thanks, Nicolai, would this then be the 'official recommended way' if I want to stay within Spec as much as possible ? | list | list := ListModel new. list title: 'List Example'; items: Smalltalk allClasses; menu: [ MenuModel new addGroup: [ :group | group addItem: [ :item | item name: 'Browse'; enabled: [ list selectedItem notNil ]; action: [ list selectedItem browse ] ] ]; buildWithSpecAsPopup ]; openWithSpec.

May 24, 2017

Re: [Pharo-users] How to add a contextual menu to a Spec

by Hartmut Krasemann

Hi Sven, > Subject: [Pharo-users] How to add a contextual menu to a Spec > ListModel > Message-ID: <5BBF6BCB-2C95-4948-932C-D14F71C0B3D9(a)stfx.eu> > Content-Type: text/plain; charset=us-ascii > > Hi, > > I am struggle a bit in find the right way to add a contextual menu to a Spec ListModel. > > Consider: > > ListModel new > title: 'List Example'; > items: Smalltalk allClasses; > openWithSpec. > > I would like to add a right-click contextual menu to the list, with for example a 'Browse' action. I can't find such a simple example. I know there is a #menu: option, I can see some usages in my image, but they seem to do different things. What would be the recommended approach ? > > ListModel new > title: 'List Example'; > items: Smalltalk allClasses; > "menu: [ ];" > openWithSpec. > > Thanks, > > Sven > > PS: Probably the reference to the #selectedItem of the ListModel for the action is hard to write in a one-liner, that is not a requirement. > I found the following to work for ListModel and MultiColumnList, e.g to add #inspect as a list item pop up : menu: [ :m | self listMenu: m ] . listMenu: m | item | item := m add: #inspect target: self selectedItem selector: #inspect . item enablementSelector: [ self selectedItem isNotNil ] . ^m Hartmut -- signatur Hartmut Krasemann KÃ¶nigsberger Str. 41 c D 22869 Schenefeld Tel. 040.8307097 Mobil 0171.6451283 Krasemann(a)acm.org

May 24, 2017