[gambit-list] print parse tree
feeley at iro.umontreal.ca
Thu Oct 22 12:08:32 EDT 2009
On 2009-10-22, at 11:57 AM, Nguyen Thai Ngoc Duy wrote:
> How can I print a parse tree, generated by parse-program from
> _front.scm? I don't know the underlying structure but REPL prints the
> result for ever, like printing a circular graph.
The problem is that the parse tree nodes have a "parent" pointer, and
this introduces cycles. The structure, defined in gsc/_ptreeadt.scm
would have to be turned into a real structure with a "define-type",
and the "parent" field marked as unprintable: . Alternatively, you
could set the readtable so that shared structures are indicated with
the #n=... syntax. Also, if you only care about the S-expression
which corresponds to a parse tree "x", call (parse-tree->expression x).
> BTW, igsc.scm is broken because _t-c-2.scm needs
> targ-obj-subtype-integer from -t-c-3.scm.
OK. I'll fix this.
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