Compile functions to Syntax Trees

Adds a kernel function SYNTAX_TREE that translates a previously coded GAP
function into a syntax tree by using GAP records.

Makefile.rules

@@ -94,6 +94,7 @@ SOURCES += src/set.c
 SOURCES += src/stats.c
 SOURCES += src/streams.c
 SOURCES += src/stringobj.c
+SOURCES += src/syntaxtree.c
 SOURCES += src/sysfiles.c
 SOURCES += src/sysmem.c
 SOURCES += src/system.c

doc/ref/language.xml

@@ -1979,6 +1979,17 @@ For examples of <K>return</K> statements, see the functions <C>fib</C> and
 
 </Section>
 
+<Section>
+    <Heading>Syntax Trees</Heading>
+
+    This section describes the tools available to manipulate &GAP; syntax
+    programmatically.
+
+    <#Include Label="SyntaxTree">
+    <#Include Label="CleanupCompiler">
+    <#Include Label="PrintCompiler">
+</Section>
+
 
 <!-- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -->
 <!--

doc/ref/makedocreldata.g

@@ -184,6 +184,7 @@ GAPInfo.ManualDataRef:= rec(
     "../../lib/string.g",
     "../../lib/string.gd",
     "../../lib/system.g",
+    "../../lib/syntaxtree.gd",
     "../../lib/teaching.g",
     "../../lib/tcsemi.gd",
     "../../lib/test.gi",

lib/read8.g

@@ -10,6 +10,9 @@ ReadLib( "overload.g"  );
 ##
 ReadLib( "compiler.g"  );
 
+ReadLib( "syntaxtree.gd" );
+ReadLib( "syntaxtree.gi" );
+
 #############################################################################
 ##
 #X  Teaching functionality

lib/syntaxtree.gd

@@ -0,0 +1,17 @@
+## syntaxtree.gd
+
+DeclareCategory("IsSyntaxTree", IsObject);
+BindGlobal("SyntaxTreeType", NewType( NewFamily( "SyntaxTreeFamily" )
+                                    , IsSyntaxTree and IsComponentObjectRep ) );
+
+##  <#GAPDoc Label="SyntaxTree">
+##  <ManSection>
+##  <Func Name="SyntaxTree" Arg='f'/>
+##
+##  <Description>
+##  Takes a GAP function <A>f</A> and returns its syntax tree.
+##
+##  </Description>
+##  </ManSection>
+##  <#/GAPDoc>
+DeclareGlobalFunction("SyntaxTree");

lib/syntaxtree.gi

@@ -0,0 +1,15 @@
+# syntaxtree.gi
+
+InstallGlobalFunction( SyntaxTree,
+function(f)
+    if (not IsFunction(f)) or IsOperation(f) or IsKernelFunction(f) then
+        Error("SyntaxTree: <f> must be a plain GAP function, not a ", TNAM_OBJ(f));
+    fi;
+    return Objectify( SyntaxTreeType, rec( file := FilenameFunc(f)
+                                         , line := StartlineFunc(f)
+                                         , tree := SYNTAX_TREE(f) ) );
+end);
+
+InstallMethod( ViewString, "for a syntax tree"
+               , [ IsSyntaxTree ]
+               , t -> "<syntax tree>" );

src/modules-builtin.c

@@ -6,6 +6,7 @@
 #include "objccoll.h"
 #include "objset.h"
 #include "profile.h"
+#include "syntaxtree.h"
 #include "vec8bit.h"
 #include "vecffe.h"
 #include "vecgf2.h"
@@ -103,6 +104,9 @@ const InitInfoFunc InitFuncsBuiltinModules[] = {
     InitInfoWeakPtr,
     InitInfoSaveLoad,
 
+    /* syntax and parser tools */
+    InitInfoSyntaxTree,
+
     /* input and output                                                    */
     InitInfoStreams,
     InitInfoSysFiles,