[#BOO-201] print AST visitor - jira.codehaus.org

Boo

print AST visitor

Created: 02/Dec/04 06:49 PM Updated: 21/Mar/05 06:11 PM

Component/s:

Compiler

Affects Version/s:

None

Fix Version/s:

0.7

Time Tracking:

Not Specified

File Attachments:

astgen.boo (20 kb)
2.

astserialize.patch (2 kb)

Description

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A visitor class that prints out the AST types. Useful when learning about the compiler and writing custom macros or attributes.

Additionally you could show the AST tree after each compiler step to visually show what each step did (you might use a "diff" tool to show differences between the tree at each step).

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Doug H - 09/Dec/04 07:07 PM

It looks like just a simple change was needed to make this work. Other changes can be made to make the xml output prettier. And you can create xslt to make it compatible with other AST representations out there like JavaML or .NET CodeDom, or do things like transfer the AST XML back into boo code.

Changes:

In boo.lang.compiler/ast/node.cs, add an [System.Xml.Serialization.XmlIgnore] above the Entity property (line 95). (otherwise you get an error because an interface type (IEntity) can't be serialized)

Add this to boo.lang.compiler/ast/statement.cs
[System.Xml.Serialization.XmlInclude(typeof(MacroStatement))]

Optional to make the XML a little prettier:

Insert this at line 255 in scripts/astgen.boo:
if field.Name == "Name":
writer.WriteLine("""
[System.Xml.Serialization.XmlAttribute]""")

Add an [System.Xml.Serialization.XmlAttribute] or [System.Xml.Serialization.XmlIgnore] above the IsSynthetic property in Node.cs.

I'll post a note to boo-dev with a sample script and its output.

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Rodrigo B. de Oliveira - 09/Dec/04 07:11 PM

Hi, Doug,

Looks good to me. Can you provide a patch (diff) with the proposed changes?

Best wishes,
Rodrigo

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Doug H - 09/Dec/04 07:29 PM

Right after I uploaded the patch, I realized I forgot to change writer.WriteLine to writer.Write in astgen.boo. Otherwise there is an extra (harmless) line break after the attribute.

+ if field.Name == "Name":
+ writer.Write("""
+ [System.Xml.Serialization.XmlAttribute]""")
+

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Doug H - 10/Dec/04 06:42 PM

Here is my copy of astgen.boo to make a few other improvements to the xml output, like printing out the modifiers of a class or method (i.e. private, public, abstract...).

Also I made this one other change:

In node.cs, add an [System.ComponentModel.DefaultValue(false)] attribute above the IsSynthetic property to suppress all those issynthetic values in the xml output.

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Doug H - 13/Dec/04 12:31 AM

You also need to add this line to Boo.Lang.Compiler/Ast/Expression.cs:

[System.Xml.Serialization.XmlInclude(typeof(TypeofExpression))]