implode-asfix — maps an asfix parse tree to an abstract syntax tree


implode-asfix [--lex] [--layout] [--lit] [--alt] [--appl] [--nt] [--inj] [--list] [--seq] [--pt] [--concrete] [-i file | --input file] [-o file | --output file] [-b] [-S | --silent] [--verbose level] [--k level | --keep level] [-h | -? | --help] [--about] [--version]


The implode-asfix utility maps an AsFix tree to an abstract syntax tree. The mapping performs several transformations, including:

  • remove layout

  • flatten lexical subtrees to strings

  • replace appl(prod(...),[...]) applications by constructor applications, if the production is annotated with a cons(...) attribute.

The input tree is required to be in AsFix2 format. See the AsFix section for more information about the AsFix format.


Implode Options


Flatten alternatives.


Replace appl applications by constructor applications.


Skip concrete syntax parts of a Stratego program. Concrete syntax starts a ToTerm, ToStrategy or ToBuild and stops at FromTerm or FromApp.


Remove injections from the parse tree.


Remove layout nodes from the parse tree.


Flatten lexical substrings to strings.


Flatten lists.


Remove literal nodes from the parse tree.


Replace appl application by non-terminal applications.


Remove the outer pt constructor from the parse tree


Replace sequences by tuples

Common Input/Output Options

-i file

The input term given by the file name file.

In the absence of the -i option, input will be read from stdin.

-o file

The output will be written to the file given by the file name file.

In the absence of the -o option, output will be written to stdout.


The output will be written in the binary (BAF) ATerm format.

ATerms in the BAF format require a lot less space than ones in the TAF format, but the Java ATerm library does not currently support baf ATerms. ATerms in the baf format is the preferred format of exchange between Stratego tools.

Common Debugging Options


See --version.

-h, -?, --help

Display usage information.

--keep int

Keep intermediate results produced by the internal stages in the pretty-printing process. This is only useful for debugging. A high value of int indicates increased eagerness for keeping intermediate results.

Default setting is 0, indicating that no intermediates will be kept.

-S, --silent

Silent execution. Same as --verbose 0.

--verbose int

Set verbosity level to numerical value int. The higher the number, the more information about pp-aterm's inner workings are printed.

Alternatively, int can be set to either of the following verbosity levels, given in increasing order of verbosity: emergency, alert, critical, error, warning, notice, info, debug, vomit.


Displays the tool name and version.


The implosion of parse trees by implode-asfix uses the cons annotation of SDF productions. For instance, the following annotation are typical for a small expression language.

module Exp
  context-free start-symbols Exp
  sorts Id IntConst Exp
  lexical syntax
    [\ \t\n]  -> LAYOUT
    [a-zA-Z]+ -> Id
    [0-9]+    -> IntConst
  context-free syntax
    Id        -> Exp {cons("Var")}
    IntConst  -> Exp {cons("Int")}
    Exp "*"  Exp -> Exp  {left, cons("Mul")}
    Exp "/"  Exp -> Exp  {left, cons("Div")}
    Exp "%"  Exp -> Exp  {left, cons("Mod")}
    Exp "+"  Exp -> Exp  {left, cons("Plus")}
    Exp "-"  Exp -> Exp  {left, cons("Minus")}
  context-free priorities
      Exp "*"  Exp -> Exp
      Exp "/"  Exp -> Exp
      Exp "%"  Exp -> Exp
  > {left:
      Exp "+"  Exp -> Exp
      Exp "-"  Exp -> Exp

Invoking sglr followed by implode-asfix results in an abstract syntax tree.

$ echo "1 + 2 * 3" | sglr -2 -p Exp.def.tbl | implode-asfix

Reporting Bugs

Please report bugs to


Copyright (C) 2002-2005 Eelco Visser

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.