mbeckerle commented on code in PR #98: URL: https://github.com/apache/daffodil-site/pull/98#discussion_r1024559443
########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -36,7 +36,108 @@ If someone wants to help please let the mailto:[email protected][dev] list know in order to avoid duplication. -=== Report hanging problem running sbt (really dev.dirs) from MSYS2 on Windows +=== Anonymous/multiple choice groups + +We already handle elements having xs:choice complex types. +In addition, we should support anonymous/multiple choice groups. +We may need to refine the choice runtime structure +in order to allow multiple choice groups +to be inlined into parent elements. +Here is an example schema +and corresponding C code to demonstrate: + +[source,xml] +---- + <xs:complexType name="NestedUnionType"> + <xs:sequence> + <xs:element name="first_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./first_tag)}"> + <xs:element name="foo" type="idl:FooType" dfdl:choiceBranchKey="1 2"/> + <xs:element name="bar" type="idl:BarType" dfdl:choiceBranchKey="3 4"/> + </xs:choice> + <xs:element name="second_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./second_tag)}"> + <xs:element name="fie" type="idl:FieType" dfdl:choiceBranchKey="1"/> + <xs:element name="fum" type="idl:FumType" dfdl:choiceBranchKey="2"/> + </xs:choice> + </xs:sequence> + </xs:complexType> +---- + +[source,c] +---- +typedef struct NestedUnion +{ + InfosetBase _base; + int32_t first_tag; + size_t _choice_1; // choice of which union field to use Review Comment: Why are these size_t ? Not at all obvious that a type intended to hold sizes is the right type for these. union_tag_t maybe? ########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -36,7 +36,108 @@ If someone wants to help please let the mailto:[email protected][dev] list know in order to avoid duplication. -=== Report hanging problem running sbt (really dev.dirs) from MSYS2 on Windows +=== Anonymous/multiple choice groups + +We already handle elements having xs:choice complex types. +In addition, we should support anonymous/multiple choice groups. +We may need to refine the choice runtime structure +in order to allow multiple choice groups +to be inlined into parent elements. +Here is an example schema +and corresponding C code to demonstrate: + +[source,xml] +---- + <xs:complexType name="NestedUnionType"> + <xs:sequence> + <xs:element name="first_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./first_tag)}"> + <xs:element name="foo" type="idl:FooType" dfdl:choiceBranchKey="1 2"/> + <xs:element name="bar" type="idl:BarType" dfdl:choiceBranchKey="3 4"/> + </xs:choice> + <xs:element name="second_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./second_tag)}"> + <xs:element name="fie" type="idl:FieType" dfdl:choiceBranchKey="1"/> + <xs:element name="fum" type="idl:FumType" dfdl:choiceBranchKey="2"/> + </xs:choice> + </xs:sequence> + </xs:complexType> +---- + +[source,c] +---- +typedef struct NestedUnion +{ + InfosetBase _base; + int32_t first_tag; + size_t _choice_1; // choice of which union field to use + union + { + foo foo; + bar bar; + }; + int32_t second_tag; + size_t _choice_2; // choice of which union field to use + union + { + fie fie; + fum fum; + }; +} NestedUnion; +---- + +=== Arrays + +Instead of expanding arrays inline within childrenERDs, +we may want to store a single entry +for an array in childrenERDs +giving the array's offset and size of all its elements. Review Comment: by "size of all its elements" you mean in total? or of each of its elements? I think you mean the total size since each child element could be a different size (if they are variable length). ########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -109,141 +211,26 @@ and try the parse call again as an attempt to resynchronize with a correct data stream after a bunch of failures. -Note that we actually run the generated code in an embedded processor +Note that we sometimes run the generated code in an embedded processor and call our own fread/frwrite functions which replace the stdio fread/fwrite functions since the C code runs bare metal without OS functions. -We can implement fseek but we should have a good use case. - -=== Javadoc-like tool for C code - -We should consider adopting one of the javadoc-like tools for C code -and structuring our comments that way. +We can implement the fseek function on the embedded processor too +but we would need a good use case requiring recovering after errors. === Validate "fixed" values in runtime1 too If we change runtime1 to validate "fixed" values like runtime2 does, then we can resolve https://issues.apache.org/jira/browse/DAFFODIL-117[DAFFODIL-117]. -=== Improve TDML Runner - -We want to improve the TDML Runner -to make it easier to run TDML tests -with both runtime1 and runtime2. -We want to eliminate the need -to configure a `daf:tdmlImplementation` tunable -in the TDML test using 12 lines of code. - -I had an initial idea which was that -the TDML Runner could run both runtime1 and runtime2 -automatically (in parallel or serially) -if it sees a TDML root attribute -saying `defaultImplementations="daffodil daffodil-runtime2"` -or a parser/unparseTestCase attribute -saying `implementations="daffodil daffodil-runtime2"`. -To make running the same test on runtime1/runtime2 easier -we also could add an implementation attribute -to tdml:errors/warnings elements -saying which implementation they are for -and tell the TDML Runner to check errors/warnings -for runtime2 as well as runtime1. - -Then I had another idea which might be easier to implement. -If we could find a way to set Daffodil's tdmlImplementation tunable -using a command line option or environment variable -or some other way to change TDML Runner's behavior -when running both "sbt test" and "daffodil test" -then we could simply run "sbt test" or "daffodil test" twice -(first using runtime1 and then using runtime2) -in order to verify all the cross tests work on both. -I think this way would be easier than making TDML Runner -automatically run all the implementations it can find -in parallel or serially when running cross tests. - -If the second idea works as I hope it does, -then we can start the process of adding "daffodil-runtime2" -to some of the cross tests we have for daffodil and ibm. -We also chould change ibm's ProcessFactory class -to have a different name than daffodil's ProcessFactory class -and update TDML Runner's match expression to use the new class name. -Then some developers could add the ibmDFDLCrossTester plugin -to their daffodil checkout permanently -instead of having to do & undo that change -each time they want to run daffodil/ibm cross tests. - -=== C struct/field name collisions - -To avoid possible name collisions, -we should prepend struct names and field names with namespace prefixes -if their infoset elements have non-null namespace prefixes. -Alternatively, we may need to use enclosing elements' names -as prefixes to avoid name collisions without namespaces. - -=== Anonymous/multiple choice groups - -We already handle elements having xs:choice complex types. -In addition, we should support anonymous/multiple choice groups. -We may need to refine the choice runtime structure -in order to allow multiple choice groups -to be inlined into parent elements. -Here is an example schema -and corresponding C code to demonstrate: - -[source,xml] ----- - <xs:complexType name="NestedUnionType"> - <xs:sequence> - <xs:element name="first_tag" type="idl:int32"/> - <xs:choice dfdl:choiceDispatchKey="{xs:string(./first_tag)}"> - <xs:element name="foo" type="idl:FooType" dfdl:choiceBranchKey="1 2"/> - <xs:element name="bar" type="idl:BarType" dfdl:choiceBranchKey="3 4"/> - </xs:choice> - <xs:element name="second_tag" type="idl:int32"/> - <xs:choice dfdl:choiceDispatchKey="{xs:string(./second_tag)}"> - <xs:element name="fie" type="idl:FieType" dfdl:choiceBranchKey="1"/> - <xs:element name="fum" type="idl:FumType" dfdl:choiceBranchKey="2"/> - </xs:choice> - </xs:sequence> - </xs:complexType> ----- - -[source,c] ----- -typedef struct NestedUnion -{ - InfosetBase _base; - int32_t first_tag; - size_t _choice_1; // choice of which union field to use - union - { - foo foo; - bar bar; - }; - int32_t second_tag; - size_t _choice_2; // choice of which union field to use - union - { - fie fie; - fum fum; - }; -} NestedUnion; ----- - -=== Choice dispatch key expressions - -We currently support only a very restricted -and simple subset of choice dispatch key expressions. -We would like to refactor the DPath expression compiler -and make it generate C code -in order to support arbitrary choice dispatch key expressions. - === No match between choice dispatch key and choice branch keys -Right now c-daffodil is more strict than scala-daffodil +Right now c/daffodil is more strict than daffodil when unparsing infoset XML files with no matches (or mismatches) between choice dispatch keys and branch keys. -Perhaps c-daffodil should load such an XML file +Such a situation always makes c/daffodil exit with an error. +Perhaps c/daffodil should load such an XML file Review Comment: Agreed. The choiceDispatchKey should not be evaluated at unparse time. Only at parse time. dfdl:outputValueCalc is needed to update elements such that on a re-parse, the choiceDispatchKey value *will be* the right one matching the unparsed choice branch. But that's not automatic. Schema authors must write the dfdl:outputValueCalcs to ensure this. ########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -52,7 +153,8 @@ coursier picks up the new directories version, sbt picks up the new coursier version, and daffodil picks up the new sbt version, before we can remove the "echo >> $GITHUB_ENV" lines -from .github/workflows/main.yml. +from .github/workflows/main.yml +which prevent the sbt hanging problem. Review Comment: Below is discussion of backtracking. I didn't think we were going to allow backtracking or forward speculation. Deterministic subset of DFDL being the target. This means parse errors are fatal. Is this something you are thinking we should revisit? ########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -36,7 +36,108 @@ If someone wants to help please let the mailto:[email protected][dev] list know in order to avoid duplication. -=== Report hanging problem running sbt (really dev.dirs) from MSYS2 on Windows +=== Anonymous/multiple choice groups + +We already handle elements having xs:choice complex types. +In addition, we should support anonymous/multiple choice groups. Review Comment: Not so sure. I'm perfectly fine with disallowing anonymous choices. @stevedlawrence and I were looking at DFDL integration for other systems like Apache Drill, NiFi, Avro, etc. and they generally do not allow anonymous choices. Hence, any DFDL schema that has anonymous choices doesn't integrate well with any of those unless we generate a child element with a generated name, and that makes paths awkward, etc. Maybe we just say the Runtime2 DFDL subset doesn't allow anonymous choices? ########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -36,7 +36,108 @@ If someone wants to help please let the mailto:[email protected][dev] list know in order to avoid duplication. -=== Report hanging problem running sbt (really dev.dirs) from MSYS2 on Windows +=== Anonymous/multiple choice groups + +We already handle elements having xs:choice complex types. +In addition, we should support anonymous/multiple choice groups. +We may need to refine the choice runtime structure +in order to allow multiple choice groups +to be inlined into parent elements. +Here is an example schema +and corresponding C code to demonstrate: + +[source,xml] +---- + <xs:complexType name="NestedUnionType"> + <xs:sequence> + <xs:element name="first_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./first_tag)}"> + <xs:element name="foo" type="idl:FooType" dfdl:choiceBranchKey="1 2"/> + <xs:element name="bar" type="idl:BarType" dfdl:choiceBranchKey="3 4"/> + </xs:choice> + <xs:element name="second_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./second_tag)}"> + <xs:element name="fie" type="idl:FieType" dfdl:choiceBranchKey="1"/> + <xs:element name="fum" type="idl:FumType" dfdl:choiceBranchKey="2"/> + </xs:choice> + </xs:sequence> + </xs:complexType> +---- + +[source,c] +---- +typedef struct NestedUnion +{ + InfosetBase _base; + int32_t first_tag; + size_t _choice_1; // choice of which union field to use + union + { + foo foo; + bar bar; + }; + int32_t second_tag; + size_t _choice_2; // choice of which union field to use + union + { + fie fie; + fum fum; + }; +} NestedUnion; +---- + +=== Arrays + +Instead of expanding arrays inline within childrenERDs, +we may want to store a single entry +for an array in childrenERDs +giving the array's offset and size of all its elements. +We would have to write code +for special case treatment of array member fields +versus scalar member fields +but we could save space/memory in childrenERDs Review Comment: Agreed. We really want arrays to be efficient. No per-element overhead for ERDs. This means an "array child" (child within an array) has a distinct representation from an element child. Or maybe the general case is arrays, and scalar children are treated as array children with min/maxOccurs 1. ########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -36,7 +36,108 @@ If someone wants to help please let the mailto:[email protected][dev] list know in order to avoid duplication. -=== Report hanging problem running sbt (really dev.dirs) from MSYS2 on Windows +=== Anonymous/multiple choice groups + +We already handle elements having xs:choice complex types. +In addition, we should support anonymous/multiple choice groups. +We may need to refine the choice runtime structure +in order to allow multiple choice groups +to be inlined into parent elements. +Here is an example schema +and corresponding C code to demonstrate: + +[source,xml] +---- + <xs:complexType name="NestedUnionType"> + <xs:sequence> + <xs:element name="first_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./first_tag)}"> + <xs:element name="foo" type="idl:FooType" dfdl:choiceBranchKey="1 2"/> + <xs:element name="bar" type="idl:BarType" dfdl:choiceBranchKey="3 4"/> + </xs:choice> + <xs:element name="second_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./second_tag)}"> + <xs:element name="fie" type="idl:FieType" dfdl:choiceBranchKey="1"/> + <xs:element name="fum" type="idl:FumType" dfdl:choiceBranchKey="2"/> + </xs:choice> + </xs:sequence> + </xs:complexType> +---- + +[source,c] +---- +typedef struct NestedUnion +{ + InfosetBase _base; + int32_t first_tag; + size_t _choice_1; // choice of which union field to use + union + { + foo foo; + bar bar; + }; + int32_t second_tag; + size_t _choice_2; // choice of which union field to use + union + { + fie fie; + fum fum; + }; +} NestedUnion; +---- + +=== Arrays + +Instead of expanding arrays inline within childrenERDs, +we may want to store a single entry +for an array in childrenERDs +giving the array's offset and size of all its elements. +We would have to write code +for special case treatment of array member fields +versus scalar member fields +but we could save space/memory in childrenERDs +for use cases with very large arrays. +An array element's ERD should have minOccurs and maxOccurs +where minOccurs is unsigned +and maxOccurs is signed with -1 meaning "unbounded". +The actual number of children in an array instance +would have to be stored with the array instance +in the C struct or the ERD. +An array node has to be a different kind of infoset node +with a place for this number of actual children to be stored. +Probably all ERDs should just get minOccurs and maxOccurs +and a scalar is just one with 1, 1 as those values, +an optional element is 0, 1, +and an array is all other legal combinations +like N, -1 and N, and M with N<=M. +A restriction that minOccurs is 0, 1, +or equal to maxOccurs (which is not -1) +is acceptable. +A restriction that maxOccurs is 1, -1, +or equal to minOccurs +is also fine +(means variable-length arrays always have unbounded number of elements). Review Comment: I'm fine with this restriction as well. ########## site/dev/design-notes/runtime2-todos.adoc: ########## @@ -36,7 +36,108 @@ If someone wants to help please let the mailto:[email protected][dev] list know in order to avoid duplication. -=== Report hanging problem running sbt (really dev.dirs) from MSYS2 on Windows +=== Anonymous/multiple choice groups + +We already handle elements having xs:choice complex types. +In addition, we should support anonymous/multiple choice groups. +We may need to refine the choice runtime structure +in order to allow multiple choice groups +to be inlined into parent elements. +Here is an example schema +and corresponding C code to demonstrate: + +[source,xml] +---- + <xs:complexType name="NestedUnionType"> + <xs:sequence> + <xs:element name="first_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./first_tag)}"> + <xs:element name="foo" type="idl:FooType" dfdl:choiceBranchKey="1 2"/> + <xs:element name="bar" type="idl:BarType" dfdl:choiceBranchKey="3 4"/> + </xs:choice> + <xs:element name="second_tag" type="idl:int32"/> + <xs:choice dfdl:choiceDispatchKey="{xs:string(./second_tag)}"> + <xs:element name="fie" type="idl:FieType" dfdl:choiceBranchKey="1"/> + <xs:element name="fum" type="idl:FumType" dfdl:choiceBranchKey="2"/> + </xs:choice> + </xs:sequence> + </xs:complexType> +---- + +[source,c] +---- +typedef struct NestedUnion +{ + InfosetBase _base; + int32_t first_tag; + size_t _choice_1; // choice of which union field to use + union + { + foo foo; + bar bar; + }; + int32_t second_tag; + size_t _choice_2; // choice of which union field to use + union + { + fie fie; + fum fum; + }; +} NestedUnion; +---- + +=== Arrays + +Instead of expanding arrays inline within childrenERDs, +we may want to store a single entry +for an array in childrenERDs +giving the array's offset and size of all its elements. +We would have to write code +for special case treatment of array member fields +versus scalar member fields +but we could save space/memory in childrenERDs +for use cases with very large arrays. +An array element's ERD should have minOccurs and maxOccurs +where minOccurs is unsigned +and maxOccurs is signed with -1 meaning "unbounded". +The actual number of children in an array instance +would have to be stored with the array instance +in the C struct or the ERD. +An array node has to be a different kind of infoset node +with a place for this number of actual children to be stored. +Probably all ERDs should just get minOccurs and maxOccurs +and a scalar is just one with 1, 1 as those values, Review Comment: Ah. Same thought. What crosses my mind now, is that all these ERDs, even tough it is one per array, are mostly all statically known in the metadata (ERD) of the enclosing parent element. I feel like we should be storing more ERD pointers in parent ERDs and not needing them in instance info in more cases. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
