Okay, I think I almost have a solution. I now collect all the actions from
the rules with the function:
function collect_rules(rule::Rule, lst::Array)
push!(lst, rule)
for child in get_children(rule)
collect_rules(child, lst)
end
return lst
end
which is called from the loop:
all_rules = Rule[]
code = {}
for definition in expr.args[2:2:end]
name = string(definition.args[1])
ref_by_name = Expr(:ref, :rules, name)
rule = parseDefinition(name, definition.args[2], pdata)
push!(code, :(rules[$name] = $rule))
all_rules = collect_rules(rule, all_rules)
end
Finally, I add the transform to all the actions in the loop:
for rule in all_rules
if typeof(rule.action) != Function
dot = Expr(:(.), rule, QuoteNode(:action))
fn = Expr(:(->),
Expr(:tuple, :rule, :value, :first, :last, :children),
Expr(:block, rule.action))
push!(code, Expr(:(=), dot, fn))
end
end
Unfortunately, I'm still getting the namespace problem. I assume this is
because I'm not escaping properly in the macro. However, after playing
around with different variations, I can't figure out the proper place to
put the escape.
Thanks for all the help!
On Sunday, March 22, 2015 at 10:02:28 AM UTC-4, Jameson wrote:
>
> the trick with macros is that everything should be generating code, not
> actually evaluating that code. think of it as a series of functions that do
> a text transformation to a new structured document, not a [partial]
> execution of that document. for example:
>
> function parseDefinition(name::String, expr::Expr, pdata::ParserData)
> #...
> elseif expr.head === :curly
> action_expr = expand_names(expr.args[2])
> rule_expr = parseDefinition(name, expr.args[1], action_expr, pdata)
> else
> #...
> return rule_expr
> end
> macro doAction(expr)
> return parseDefinition(..., expr, ...)
> end
>
> On Sun, Mar 22, 2015 at 8:15 AM Abe Schneider [email protected]
> <http://mailto:[email protected]> wrote:
>
> I'm in the process of trying to figure out how to do something similar to
>> that, but it's unfortunately not easy. I was hoping that there might be a
>> method to insert an expression into the AST without an eval required, as it
>> would greatly simplify the code Jameson suggested using the `insert` macro,
>> which does as advertised, expect for the namespace issue.
>>
>>
>
