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separate ASTVisitor.visit for ExpressionNode
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abstract classes should not have visitor functions, but rather only do
dynamic dispatch. This becomes more important later with dlang-community#409
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@WebFreak001
WebFreak001 committed Mar 23, 2023
1 parent 98bf0f4 commit edd03fa
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Showing 2 changed files with 67 additions and 42 deletions.
33 changes: 29 additions & 4 deletions src/dparse/ast.d
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Original file line number Diff line number Diff line change
Expand Up @@ -92,11 +92,32 @@ enum DeclarationListStyle : ubyte
*/
abstract class ASTVisitor
{

/** */
deprecated("Don't use or override visit(ExpressionNode). For usage: dynamicDispatch(ExpressionNode) is equivalent; "
~ "for overriding: you should probably override more specific cases. If you need to override to inject some "
~ "before/after code for all cases, make sure to call `super.dynamicDispatch(n)` instead of `n.accept(this)`!")
void visit(const ExpressionNode n)
{
switch (typeMap[typeid(n)])
dynamicDispatch(n);
}

/**
* Looks at the runtime type of `n`, then calls the appropriate `visit`
* method at runtime.
*
* Rule of thumb: when the type is an abstract class, use `dynamicDispatch`,
* otherwise use `visit`.
*
* For templated calls:
* ---
* static if (__traits(isAbstractClass, typeof(node)))
* visitor.dynamicDispatch(node);
* else
* visitor.visit(node);
* ---
*/
void dynamicDispatch(const ExpressionNode n)
{
switch (typeMap.get(typeid(n), 0))
{
case 1: visit(cast(AddExpression) n); break;
case 2: visit(cast(AndAndExpression) n); break;
Expand Down Expand Up @@ -383,11 +404,15 @@ template visitIfNotNull(fields ...)
{
static if (typeof(fields[0]).stringof[$ - 2 .. $] == "[]")
{
static if (__traits(hasMember, typeof(fields[0][0]), "classinfo"))
static if (__traits(isAbstractClass, typeof(fields[0][0])))
immutable visitIfNotNull = "foreach (i; " ~ fields[0].stringof ~ ") if (i !is null) visitor.dynamicDispatch(i);\n";
else static if (__traits(hasMember, typeof(fields[0][0]), "classinfo"))
immutable visitIfNotNull = "foreach (i; " ~ fields[0].stringof ~ ") if (i !is null) visitor.visit(i);\n";
else
immutable visitIfNotNull = "foreach (i; " ~ fields[0].stringof ~ ") visitor.visit(i);\n";
}
else static if (__traits(isAbstractClass, typeof(fields[0])))
immutable visitIfNotNull = "if (" ~ fields[0].stringof ~ " !is null) visitor.dynamicDispatch(" ~ fields[0].stringof ~ ");\n";
else static if (__traits(hasMember, typeof(fields[0]), "classinfo"))
immutable visitIfNotNull = "if (" ~ fields[0].stringof ~ " !is null) visitor.visit(" ~ fields[0].stringof ~ ");\n";
else static if (is(Unqual!(typeof(fields[0])) == Token))
Expand Down
76 changes: 38 additions & 38 deletions src/dparse/astprinter.d
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,12 +23,12 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<addExpression operator=\"", str(addExpression.operator), "\">");
output.writeln("<left>");
visit(addExpression.left);
dynamicDispatch(addExpression.left);
output.writeln("</left>");
if (addExpression.right !is null)
{
output.writeln("<right>");
visit(addExpression.right);
dynamicDispatch(addExpression.right);
output.writeln("</right>");
}
output.writeln("</addExpression>");
Expand Down Expand Up @@ -58,12 +58,12 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<andAndExpression>");
output.writeln("<left>");
visit(andAndExpression.left);
dynamicDispatch(andAndExpression.left);
output.writeln("</left>");
if (andAndExpression.right !is null)
{
output.writeln("<right>");
visit(andAndExpression.right);
dynamicDispatch(andAndExpression.right);
output.writeln("</right>");
}
output.writeln("</andAndExpression>");
Expand All @@ -73,12 +73,12 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<andExpression>");
output.writeln("<left>");
visit(andExpression.left);
dynamicDispatch(andExpression.left);
output.writeln("</left>");
if (andExpression.right !is null)
{
output.writeln("<right>");
visit(andExpression.right);
dynamicDispatch(andExpression.right);
output.writeln("</right>");
}
output.writeln("</andExpression>");
Expand Down Expand Up @@ -191,13 +191,13 @@ class XMLPrinter : ASTVisitor
if (caseRangeStatement.low !is null)
{
output.writeln("<low>");
visit(caseRangeStatement.low);
dynamicDispatch(caseRangeStatement.low);
output.writeln("</low>");
}
if (caseRangeStatement.high !is null)
{
output.writeln("<high>");
visit(caseRangeStatement.high);
dynamicDispatch(caseRangeStatement.high);
output.writeln("</high>");
}
if (caseRangeStatement.declarationsAndStatements !is null)
Expand Down Expand Up @@ -295,7 +295,7 @@ class XMLPrinter : ASTVisitor
if (deprecated_.assignExpression !is null)
{
output.writeln("<deprecated>");
visit(deprecated_.assignExpression);
dynamicDispatch(deprecated_.assignExpression);
output.writeln("</deprecated>");
}
else
Expand All @@ -320,7 +320,7 @@ class XMLPrinter : ASTVisitor
visit(enumMember.type);
output.write("<name>", enumMember.name.text, "</name>");
if (enumMember.assignExpression !is null)
visit(enumMember.assignExpression);
dynamicDispatch(enumMember.assignExpression);
output.writeln("</anonymousEnumMember>");
}

Expand All @@ -336,10 +336,10 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<equalExpression operator=\"", str(equalExpression.operator), "\">");
output.writeln("<left>");
visit(equalExpression.left);
dynamicDispatch(equalExpression.left);
output.writeln("</left>");
output.writeln("<right>");
visit(equalExpression.right);
dynamicDispatch(equalExpression.right);
output.writeln("</right>");
output.writeln("</equalExpression>");
}
Expand Down Expand Up @@ -475,10 +475,10 @@ class XMLPrinter : ASTVisitor
else
output.writeln("<identityExpression operator=\"is\">");
output.writeln("<left>");
visit(identityExpression.left);
dynamicDispatch(identityExpression.left);
output.writeln("</left>");
output.writeln("<right>");
visit(identityExpression.right);
dynamicDispatch(identityExpression.right);
output.writeln("</right>");
output.writeln("</identityExpression>");
}
Expand Down Expand Up @@ -541,10 +541,10 @@ class XMLPrinter : ASTVisitor
else
output.writeln("<inExpression operator=\"in\">");
output.writeln("<left>");
visit(inExpression.left);
dynamicDispatch(inExpression.left);
output.writeln("</left>");
output.writeln("<right>");
visit(inExpression.right);
dynamicDispatch(inExpression.right);
output.writeln("</right>");
output.writeln("</inExpression>");
}
Expand Down Expand Up @@ -613,10 +613,10 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<keyValuePair>");
output.writeln("<key>");
visit(keyValuePair.key);
dynamicDispatch(keyValuePair.key);
output.writeln("</key>");
output.writeln("<value>");
visit(keyValuePair.value);
dynamicDispatch(keyValuePair.value);
output.writeln("</value>");
output.writeln("</keyValuePair>");
}
Expand Down Expand Up @@ -676,12 +676,12 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<mulExpression operator=\"", str(mulExpression.operator), "\">");
output.writeln("<left>");
visit(mulExpression.left);
dynamicDispatch(mulExpression.left);
output.writeln("</left>");
if (mulExpression.right !is null)
{
output.writeln("<right>");
visit(mulExpression.right);
dynamicDispatch(mulExpression.right);
output.writeln("</right>");
}
output.writeln("</mulExpression>");
Expand All @@ -691,12 +691,12 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<orOrExpression>");
output.writeln("<left>");
visit(orOrExpression.left);
dynamicDispatch(orOrExpression.left);
output.writeln("</left>");
if (orOrExpression.right !is null)
{
output.writeln("<right>");
visit(orOrExpression.right);
dynamicDispatch(orOrExpression.right);
output.writeln("</right>");
}
output.writeln("</orOrExpression>");
Expand Down Expand Up @@ -727,12 +727,12 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<powExpression>");
output.writeln("<left>");
visit(powExpression.left);
dynamicDispatch(powExpression.left);
output.writeln("</left>");
if (powExpression.right !is null)
{
output.writeln("<right>");
visit(powExpression.right);
dynamicDispatch(powExpression.right);
output.writeln("</right>");
}
output.writeln("</powExpression>");
Expand All @@ -743,10 +743,10 @@ class XMLPrinter : ASTVisitor
output.writeln("<relExpression operator=\"",
xmlAttributeEscape(str(relExpression.operator)), "\">");
output.writeln("<left>");
visit(relExpression.left);
dynamicDispatch(relExpression.left);
output.writeln("</left>");
output.writeln("<right>");
visit(relExpression.right);
dynamicDispatch(relExpression.right);
output.writeln("</right>");
output.writeln("</relExpression>");
}
Expand All @@ -768,10 +768,10 @@ class XMLPrinter : ASTVisitor
output.writeln("<shiftExpression operator=\"",
xmlAttributeEscape(str(shiftExpression.operator)), "\">");
output.writeln("<left>");
visit(shiftExpression.left);
dynamicDispatch(shiftExpression.left);
output.writeln("</left>");
output.writeln("<right>");
visit(shiftExpression.right);
dynamicDispatch(shiftExpression.right);
output.writeln("</right>");
output.writeln("</shiftExpression>");
}
Expand Down Expand Up @@ -804,7 +804,7 @@ class XMLPrinter : ASTVisitor
if (templateAliasParameter.colonExpression !is null)
{
output.writeln("<specialization>");
visit(templateAliasParameter.colonExpression);
dynamicDispatch(templateAliasParameter.colonExpression);
output.writeln("</specialization>");
}
else if (templateAliasParameter.colonType !is null)
Expand All @@ -817,7 +817,7 @@ class XMLPrinter : ASTVisitor
if (templateAliasParameter.assignExpression !is null)
{
output.writeln("<default>");
visit(templateAliasParameter.assignExpression);
dynamicDispatch(templateAliasParameter.assignExpression);
output.writeln("</default>");
}
else if (templateAliasParameter.assignType !is null)
Expand Down Expand Up @@ -962,14 +962,14 @@ class XMLPrinter : ASTVisitor
if (typeSuffix.high !is null)
{
output.writeln("<low>");
visit(typeSuffix.low);
dynamicDispatch(typeSuffix.low);
output.writeln("</low>");
output.writeln("<high>");
visit(typeSuffix.high);
dynamicDispatch(typeSuffix.high);
output.writeln("</high>");
}
else
visit(typeSuffix.low);
dynamicDispatch(typeSuffix.low);
output.writeln("</typeSuffix>");
}
}
Expand Down Expand Up @@ -1041,12 +1041,12 @@ class XMLPrinter : ASTVisitor
{
output.writeln("<xorExpression>");
output.writeln("<left>");
visit(xorExpression.left);
dynamicDispatch(xorExpression.left);
output.writeln("</left>");
if (xorExpression.right !is null)
{
output.writeln("<right>");
visit(xorExpression.right);
dynamicDispatch(xorExpression.right);
output.writeln("</right>");
}
output.writeln("</xorExpression>");
Expand All @@ -1058,15 +1058,15 @@ class XMLPrinter : ASTVisitor
if (index.high)
{
output.writeln("<low>");
visit(index.low);
dynamicDispatch(index.low);
output.writeln("</low>");

output.writeln("<high>");
visit(index.high);
dynamicDispatch(index.high);
output.writeln("</high>");
}
else
visit(index.low);
dynamicDispatch(index.low);
output.writeln("</index>");
}

Expand Down

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