C++20 concepts: added support for parsing requires-clauses

8 files changed, 225 insertions, 27 deletions

diff --git a/src/classdef.cpp b/src/classdef.cpp
index 542147a..6432e2a 100644
--- a/src/classdef.cpp
+++ b/src/classdef.cpp
@@ -239,6 +239,7 @@ class ClassDefImpl : public DefinitionMixin<ClassDefMutable>
     virtual bool subGrouping() const;
     virtual bool isSliceLocal() const;
     virtual bool hasNonReferenceSuperClass() const;
+    virtual QCString requiresClause() const;
     virtual ClassDef *insertTemplateInstance(const QCString &fileName,int startLine,int startColumn,
                                 const QCString &templSpec,bool &freshInstance) const;
 
@@ -309,6 +310,7 @@ class ClassDefImpl : public DefinitionMixin<ClassDefMutable>
                  MemberListType lt,const QCString &title,
                  const char *subTitle=0,bool showInline=FALSE,const ClassDef *inheritedFrom=0,
                  int lt2=-1,bool invert=FALSE,bool showAlways=FALSE) const;
+    virtual void setRequiresClause(const char *req);
 
   private:
     void addUsedInterfaceClasses(MemberDef *md,const char *typeStr);
@@ -527,6 +529,8 @@ class ClassDefAliasImpl : public DefinitionAliasMixin<ClassDef>
     { return getCdAlias()->isSliceLocal(); }
     virtual bool hasNonReferenceSuperClass() const
     { return getCdAlias()->hasNonReferenceSuperClass(); }
+    virtual QCString requiresClause() const
+    { return getCdAlias()->requiresClause(); }
 
     virtual int countMembersIncludingGrouped(MemberListType lt,const ClassDef *inheritedFrom,bool additional) const
     { return getCdAlias()->countMembersIncludingGrouped(lt,inheritedFrom,additional); }
@@ -704,6 +708,9 @@ class ClassDefImpl::IMPL
     uint64 spec = 0;
 
     QCString metaData;
+
+    /** C++20 requires clause */
+    QCString requiresClause;
 };
 
 void ClassDefImpl::IMPL::init(const char *defFileName, const char *name,
@@ -3184,6 +3191,16 @@ bool ClassDefImpl::hasNonReferenceSuperClass() const
   return found;
 }
 
+QCString ClassDefImpl::requiresClause() const
+{
+  return m_impl->requiresClause;
+}
+
+void ClassDefImpl::setRequiresClause(const char *req)
+{
+  m_impl->requiresClause = req;
+}
+
 /*! called from MemberDef::writeDeclaration() to (recursively) write the
  *  definition of an anonymous struct, union or class.
  */
diff --git a/src/classdef.h b/src/classdef.h
index d6c515d..b3e3325 100644
--- a/src/classdef.h
+++ b/src/classdef.h
@@ -358,6 +358,8 @@ class ClassDef : public Definition
     virtual bool isSliceLocal() const = 0;
     virtual bool hasNonReferenceSuperClass() const = 0;
 
+    virtual QCString requiresClause() const = 0;
+
     //-----------------------------------------------------------------------------------
     // --- count members ----
     //-----------------------------------------------------------------------------------
@@ -405,6 +407,7 @@ class ClassDefMutable : public DefinitionMutable, public ClassDef
     virtual void setTagLessReference(const ClassDef *cd) = 0;
     virtual void setName(const char *name) = 0;
     virtual void setMetaData(const char *md) = 0;
+    virtual void setRequiresClause(const char *req) = 0;
 
     //-----------------------------------------------------------------------------------
     // --- actions ----
diff --git a/src/doxygen.cpp b/src/doxygen.cpp
index d5e082d..9a9342b 100644
--- a/src/doxygen.cpp
+++ b/src/doxygen.cpp
@@ -1011,6 +1011,10 @@ static void addClassToContext(const Entry *root)
         cd->setTemplateArguments(*tArgList);
       }
     }
+    if (cd->requiresClause().isEmpty() && !root->req.isEmpty())
+    {
+      cd->setRequiresClause(root->req);
+    }
 
     cd->setCompoundType(convertToCompoundType(root->section,root->spec));
 
@@ -1081,6 +1085,7 @@ static void addClassToContext(const Entry *root)
       {
         cd->setTemplateArguments(*tArgList);
       }
+      cd->setRequiresClause(root->req);
       cd->setProtection(root->protection);
       cd->setIsStatic(root->stat);
 
@@ -1365,6 +1370,7 @@ static ClassDefMutable *createTagLessInstance(const ClassDef *rootCd,const Class
         imd->setMemberSpecifiers(md->getMemberSpecifiers());
         imd->setMemberGroupId(md->getMemberGroupId());
         imd->setInitializer(md->initializer());
+        imd->setRequiresClause(md->requiresClause());
         imd->setMaxInitLines(md->initializerLines());
         imd->setBitfields(md->bitfieldString());
         imd->setLanguage(md->getLanguage());
@@ -1982,6 +1988,7 @@ static void findUsingDeclImports(const Entry *root)
                 newMd->setBodySegment(md->getDefLine(),md->getStartBodyLine(),md->getEndBodyLine());
                 newMd->setBodyDef(md->getBodyDef());
                 newMd->setInitializer(md->initializer());
+                newMd->setRequiresClause(md->requiresClause());
                 newMd->setMaxInitLines(md->initializerLines());
                 newMd->setMemberGroupId(root->mGrpId);
                 newMd->setMemberSpecifiers(md->getMemberSpecifiers());
@@ -3104,6 +3111,7 @@ static void addMethodToClass(const Entry *root,ClassDefMutable *cd,
   md->setMemberGroupId(root->mGrpId);
   md->setTypeConstraints(root->typeConstr);
   md->setLanguage(root->lang);
+  md->setRequiresClause(root->req);
   md->setId(root->id);
   md->setBodyDef(fd);
   md->setFileDef(fd);
@@ -3213,6 +3221,7 @@ static void addGlobalFunction(const Entry *root,const QCString &rname,const QCSt
   md->addSectionsToDefinition(root->anchors);
   md->setMemberSpecifiers(root->spec);
   md->setMemberGroupId(root->mGrpId);
+  md->setRequiresClause(root->req);
 
   NamespaceDefMutable *nd = 0;
   // see if the function is inside a namespace that was not part of
@@ -5026,6 +5035,10 @@ static void addMemberDocs(const Entry *root,
     //printf("setInitializer\n");
     md->setInitializer(rootInit.c_str());
   }
+  if (md->requiresClause().isEmpty() && !root->req.isEmpty())
+  {
+    md->setRequiresClause(root->req);
+  }
 
   md->setMaxInitLines(root->initLines);
 
diff --git a/src/entry.cpp b/src/entry.cpp
index a0f8fa3..a58362c 100644
--- a/src/entry.cpp
+++ b/src/entry.cpp
@@ -108,6 +108,7 @@ Entry::Entry(const Entry &e)
   id          = e.id;
   extends     = e.extends;
   groups      = e.groups;
+  req         = e.req;
   m_fileDef   = e.m_fileDef;
 
   m_parent    = e.m_parent;
@@ -242,6 +243,7 @@ void Entry::reset()
   tArgLists.clear();
   typeConstr.reset();
   sli.clear();
+  req.resize(0);
   m_fileDef = 0;
 }
 
diff --git a/src/entry.h b/src/entry.h
index dd2b157..6ba88e8 100644
--- a/src/entry.h
+++ b/src/entry.h
@@ -295,6 +295,7 @@ class Entry
     QCString    id;           //!< libclang id
     LocalToc    localToc;
     QCString    metaData;     //!< Slice metadata
+    QCString    req;          //!< C++20 requires clause
 
     /// return the command name used to define GROUPDOC_SEC
     const char *groupDocCmd() const
diff --git a/src/memberdef.cpp b/src/memberdef.cpp
index 48291cb..38164ef 100644
--- a/src/memberdef.cpp
+++ b/src/memberdef.cpp
@@ -229,6 +229,7 @@ class MemberDefImpl : public DefinitionMixin<MemberDefMutable>
     virtual QCString getDeclType() const;
     virtual StringVector getLabels(const Definition *container) const;
     virtual const ArgumentList &typeConstraints() const;
+    virtual QCString requiresClause() const;
     virtual QCString documentation() const;
     virtual QCString briefDescription(bool abbr=FALSE) const;
     virtual QCString fieldType() const;
@@ -304,6 +305,7 @@ class MemberDefImpl : public DefinitionMixin<MemberDefMutable>
     virtual void setBriefDescription(const char *b,const char *briefFile,int briefLine);
     virtual void setInbodyDocumentation(const char *d,const char *inbodyFile,int inbodyLine);
     virtual void setHidden(bool b);
+    virtual void setRequiresClause(const char *req);
     virtual void incrementFlowKeyWordCount();
     virtual void writeDeclaration(OutputList &ol,
                    const ClassDef *cd,const NamespaceDef *nd,const FileDef *fd,const GroupDef *gd,
@@ -344,6 +346,8 @@ class MemberDefImpl : public DefinitionMixin<MemberDefMutable>
                           const QCString &cname) const;
     void _writeCategoryRelation(OutputList &ol) const;
     void _writeTagData(const DefType) const;
+    void _writeTemplatePrefix(OutputList &ol, const Definition *def,
+                              const ArgumentList &al, bool writeReqClause=true) const;
 
     static int s_indentLevel;
 
@@ -735,6 +739,8 @@ class MemberDefAliasImpl : public DefinitionAliasMixin<MemberDef>
     { return getMdAlias()->getDeclLine(); }
     virtual int getDeclColumn() const
     { return getMdAlias()->getDeclColumn(); }
+    virtual QCString requiresClause() const
+    { return getMdAlias()->requiresClause(); }
 
     virtual void warnIfUndocumented() const {}
     virtual void warnIfUndocumentedParams() const {}
@@ -1119,26 +1125,6 @@ static void writeExceptionList(OutputList &ol, const ClassDef *cd, const MemberD
   }
 }
 
-static void writeTemplatePrefix(OutputList &ol,const ArgumentList &al)
-{
-  ol.docify("template<");
-  for (auto it = al.begin(); it!=al.end();)
-  {
-    Argument a = *it;
-    ol.docify(a.type);
-    ol.docify(" ");
-    ol.docify(a.name);
-    if (a.defval.length()!=0)
-    {
-      ol.docify(" = ");
-      ol.docify(a.defval);
-    }
-    ++it;
-    if (it!=al.end()) ol.docify(", ");
-  }
-  ol.docify("> ");
-}
-
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------
@@ -1189,6 +1175,7 @@ class MemberDefImpl::IMPL
     QCString initializer;     // initializer
     QCString extraTypeChars;  // extra type info found after the argument list
     QCString enumBaseType;    // base type of the enum (C++11)
+    QCString requiresClause;  // requires clause (C++20)
     int initLines = 0;            // number of lines in the initializer
 
     uint64  memSpec = 0;          // The specifiers present for this member
@@ -2008,6 +1995,46 @@ QCString MemberDefImpl::getDeclType() const
   return ltype;
 }
 
+void MemberDefImpl::_writeTemplatePrefix(OutputList &ol, const Definition *def,
+                                         const ArgumentList &al, bool writeReqClause) const
+{
+  ol.docify("template<");
+  for (auto it = al.begin(); it!=al.end();)
+  {
+    Argument a = *it;
+    linkifyText(TextGeneratorOLImpl(ol), // out
+        def,                     // scope
+        getFileDef(),            // fileScope
+        this,                    // self
+        a.type,                  // text
+        FALSE                    // autoBreak
+        );
+    ol.docify(" ");
+    ol.docify(a.name);
+    if (a.defval.length()!=0)
+    {
+      ol.docify(" = ");
+      ol.docify(a.defval);
+    }
+    ++it;
+    if (it!=al.end()) ol.docify(", ");
+  }
+  ol.docify("> ");
+  if (writeReqClause && !m_impl->requiresClause.isEmpty())
+  {
+    ol.lineBreak();
+    ol.docify("requires ");
+    linkifyText(TextGeneratorOLImpl(ol), // out
+        def,                     // scope
+        getFileDef(),            // fileScope
+        this,                    // self
+        m_impl->requiresClause,  // text
+        FALSE                    // autoBreak
+        );
+  }
+}
+
+
 void MemberDefImpl::writeDeclaration(OutputList &ol,
                const ClassDef *cd,const NamespaceDef *nd,const FileDef *fd,const GroupDef *gd,
                bool inGroup, const ClassDef *inheritedFrom,const char *inheritId) const
@@ -2086,10 +2113,11 @@ void MemberDefImpl::writeDeclaration(OutputList &ol,
   if (m_impl->tArgList.hasParameters() && getLanguage()==SrcLangExt_Cpp)
   {
     if (!isAnonType) ol.startMemberTemplateParams();
-    writeTemplatePrefix(ol,m_impl->tArgList);
+    _writeTemplatePrefix(ol,d,m_impl->tArgList);
     if (!isAnonType) ol.endMemberTemplateParams(anchor(),inheritId);
   }
 
+
   // *** write type
   QCString ltype(m_impl->type);
   if (isTypedef() && getLanguage() != SrcLangExt_Slice)
@@ -3280,7 +3308,7 @@ void MemberDefImpl::writeDocumentation(const MemberList *ml,
           {
             if (!first) ol.docify(" ");
             ol.startMemberDocPrefixItem();
-            writeTemplatePrefix(ol,tal);
+            _writeTemplatePrefix(ol,scopedContainer,tal);
             ol.endMemberDocPrefixItem();
           }
         }
@@ -3296,7 +3324,7 @@ void MemberDefImpl::writeDocumentation(const MemberList *ml,
             {
               if (!first) ol.docify(" ");
               ol.startMemberDocPrefixItem();
-              writeTemplatePrefix(ol,tal);
+              _writeTemplatePrefix(ol,scopedContainer,tal,false);
               ol.endMemberDocPrefixItem();
             }
           }
@@ -3304,7 +3332,7 @@ void MemberDefImpl::writeDocumentation(const MemberList *ml,
         if (m_impl->tArgList.hasParameters() && lang==SrcLangExt_Cpp) // function template prefix
         {
           ol.startMemberDocPrefixItem();
-          writeTemplatePrefix(ol,m_impl->tArgList);
+          _writeTemplatePrefix(ol,scopedContainer,m_impl->tArgList);
           ol.endMemberDocPrefixItem();
         }
       }
@@ -5604,6 +5632,15 @@ QCString MemberDefImpl::enumBaseType() const
   return m_impl->enumBaseType;
 }
 
+void MemberDefImpl::setRequiresClause(const char *req)
+{
+  m_impl->requiresClause = req;
+}
+
+QCString MemberDefImpl::requiresClause() const
+{
+  return m_impl->requiresClause;
+}
 
 void MemberDefImpl::cacheTypedefVal(const ClassDef*val, const QCString & templSpec, const QCString &resolvedType)
 {
diff --git a/src/memberdef.h b/src/memberdef.h
index d2d6e1d..d51fbc0 100644
--- a/src/memberdef.h
+++ b/src/memberdef.h
@@ -261,6 +261,8 @@ class MemberDef : public Definition
 
     virtual const ArgumentList &typeConstraints() const = 0;
 
+    virtual QCString requiresClause() const = 0;
+
     // overrules
     virtual QCString documentation() const = 0;
     virtual QCString briefDescription(bool abbr=FALSE) const = 0;
@@ -393,6 +395,8 @@ class MemberDefMutable : public DefinitionMutable, public MemberDef
 
     virtual void setHidden(bool b) = 0;
 
+    virtual void setRequiresClause(const char *req) = 0;
+
     //-----------------------------------------------------------------------------------
     // --- actions ----
     //-----------------------------------------------------------------------------------
diff --git a/src/scanner.l b/src/scanner.l
index 78afdab..9e719d0 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -74,6 +74,7 @@ struct scannerYY_state
   int              lastStringContext = 0;
   int              lastCurlyContext = 0;
   int              lastRoundContext = 0;
+  int              lastSharpContext = 0;
   int              lastSquareContext = 0;
   int              lastInitializerContext = 0;
   int              lastClassTemplSpecContext = 0;
@@ -139,6 +140,7 @@ struct scannerYY_state
   int              currentArgumentContext = 0;
   int              lastCopyArgStringContext = 0;
   int              lastCopyArgContext = 0;
+  int              requiresContext = 0;
   QCString        *copyArgString = 0;
   QCString         fullArgString;
   QCString         dummyRawString;
@@ -149,6 +151,7 @@ struct scannerYY_state
   QCString *pCopyQuotedString = 0;
   QCString *pCopyRoundString = 0;
   QCString *pCopyCurlyString = 0;
+  QCString *pCopySharpString = 0;
   QCString *pCopyRawString = 0;
   TextStream *pCopyCurlyGString = 0;
   TextStream *pCopyRoundGString = 0;
@@ -383,6 +386,7 @@ NONLopt [^\n]*
 %x      CopyGString
 %x      CopyPHPGString
 %x      CopyRound
+%x      CopySharp
 %x      CopyCurly
 %x      GCopyRound
 %x      GCopySquare
@@ -438,6 +442,10 @@ NONLopt [^\n]*
 %x      DocBlock
 %x      DocCopyBlock
 
+ /** C++20 concepts */
+
+%x      RequiresClause
+
 %%
 
 <NextSemi>"{"                           {
@@ -2069,6 +2077,54 @@ NONLopt [^\n]*
                                           yyextra->current->name=yytext;
                                           BEGIN(FindMembers);
                                         }
+<FindMembers>"requires"                 { // C++20 requires clause
+                                          yyextra->current->req.resize(0);
+                                          yyextra->requiresContext = YY_START;
+                                          BEGIN(RequiresClause);
+                                        }
+<RequiresClause>"("                     { // requires "(A && B)"
+                                          yyextra->current->req+=yytext;
+                                          yyextra->lastRoundContext=RequiresClause;
+                                          yyextra->pCopyRoundString=&yyextra->current->req;
+                                          yyextra->roundCount=0;
+                                          BEGIN( CopyRound ) ;
+                                        }
+<RequiresClause>{ID}                    { // something like "requires true"
+                                          if (yyextra->current->req.stripWhiteSpace().isEmpty())
+                                          {
+                                            yyextra->current->req=yytext;
+                                            BEGIN(yyextra->requiresContext);
+                                          }
+                                          else
+                                          {
+                                            REJECT;
+                                          }
+                                        }
+<RequiresClause>{SCOPENAME}{BNopt}"("   { // "requires func(x)"
+                                          yyextra->current->req+=yytext;
+                                          yyextra->lastRoundContext=RequiresClause;
+                                          yyextra->pCopyRoundString=&yyextra->current->req;
+                                          yyextra->roundCount=0;
+                                          BEGIN( CopyRound );
+                                        }
+<RequiresClause>{SCOPENAME}{BNopt}"<"   { // "requires C<S,T>"
+                                          yyextra->current->req+=yytext;
+                                          yyextra->lastSharpContext=RequiresClause;
+                                          yyextra->pCopySharpString=&yyextra->current->req;
+                                          yyextra->sharpCount=0;
+                                          BEGIN( CopySharp );
+                                        }
+<RequiresClause>"||"|"&&"             { // "requires A || B" or "requires A && B"
+                                          yyextra->current->req+=yytext;
+                                        }
+<RequiresClause>{BN}+                   {
+                                          yyextra->current->req+=' ';
+                                        }
+<RequiresClause>.                       {
+                                          unput(*yytext);
+                                          yyextra->current->req=yyextra->current->req.simplifyWhiteSpace();
+                                          BEGIN(yyextra->requiresContext);
+                                        }
 <FindMembers,FindMemberName>{SCOPENAME} {
    
                                           if (yyextra->clangParser && (yyextra->insideCpp || yyextra->insideObjC))
@@ -2948,6 +3004,59 @@ NONLopt [^\n]*
                                           *yyextra->pCopyRoundString+=*yytext;
                                         }
 
+  /* generic sharp bracket list copy rules */
+<CopySharp>\"                           {
+                                          *yyextra->pCopySharpString += *yytext;
+                                          yyextra->pCopyQuotedString=yyextra->pCopySharpString;
+                                          yyextra->lastStringContext=YY_START;
+                                          BEGIN(CopyString);
+                                        }
+<CopySharp>"<"                          {
+                                          *yyextra->pCopySharpString += *yytext;
+                                          yyextra->sharpCount++;
+                                        }
+<CopySharp>">"                          {
+                                          *yyextra->pCopySharpString += *yytext;
+                                          if (--yyextra->sharpCount<0)
+                                          {
+                                            BEGIN(yyextra->lastSharpContext);
+                                          }
+                                        }
+<CopySharp>\n                           {
+                                          lineCount(yyscanner);
+                                          *yyextra->pCopySharpString += *yytext;
+                                        }
+<CopySharp>\'                           {
+                                          if (yyextra->insidePHP)
+                                          {
+                                            yyextra->current->initializer << yytext;
+                                            yyextra->pCopyQuotedString = yyextra->pCopySharpString;
+                                            yyextra->lastStringContext=YY_START;
+                                            BEGIN(CopyPHPString);
+                                          }
+                                          else
+                                          {
+                                            *yyextra->pCopySharpString += yytext;
+                                          }
+                                        }
+<CopySharp>{CHARLIT}                    {
+                                          if (yyextra->insidePHP)
+                                          {
+                                            REJECT;
+                                          }
+                                          else
+                                          {
+                                            *yyextra->pCopySharpString+=yytext;
+                                          }
+                                        }
+<CopySharp>[^"'<>\n,]+                  {
+                                          *yyextra->pCopySharpString+=yytext;
+                                        }
+<CopySharp>.                            {
+                                          *yyextra->pCopySharpString+=*yytext;
+                                        }
+
+
   /* generic round bracket list copy rules for growable strings */
 <GCopyRound>\"                          {
                                           *yyextra->pCopyRoundGString << *yytext;
@@ -4627,6 +4736,11 @@ NONLopt [^\n]*
                                           unput(*yytext);
                                           BEGIN(FuncQual);
                                         }
+<TrailingReturn>"requires"{BN}+         {
+                                          yyextra->requiresContext = FuncQual;
+                                          yyextra->current->req+=' ';
+                                          BEGIN(RequiresClause);
+                                        }
 <TrailingReturn>"("                     {
                                           yyextra->roundCount++;
                                           yyextra->current->argList.setTrailingReturnType(yyextra->current->argList.trailingReturnType()+yytext);
@@ -4734,8 +4848,15 @@ NONLopt [^\n]*
                                           yyextra->current->args += *yytext;
                                           lineCount(yyscanner);
                                         }
-<FuncQual>{ID}                          { // typically a K&R style C function
-                                          if (yyextra->insideCS && qstrcmp(yytext,"where")==0)
+<FuncQual>{ID}                          {
+                                          if (yyextra->insideCpp && qstrcmp(yytext,"requires")==0)
+                                          {
+                                            // c++20 trailing requires clause
+                                            yyextra->requiresContext = YY_START;
+                                            yyextra->current->req+=' ';
+                                            BEGIN(RequiresClause);
+                                          }
+                                          else if (yyextra->insideCS && qstrcmp(yytext,"where")==0)
                                           {
                                             // type constraint for a method
                                             yyextra->current->typeConstr.clear();
@@ -4743,7 +4864,7 @@ NONLopt [^\n]*
                                             yyextra->lastCSConstraint = YY_START;
                                             BEGIN( CSConstraintName );
                                           }
-                                          else if (checkForKnRstyleC(yyscanner))
+                                          else if (checkForKnRstyleC(yyscanner)) // K&R style C function
                                           {
                                             yyextra->current->args = yytext;
                                             yyextra->oldStyleArgType.resize(0);