15.4.237  src/lib/compiler/back/low/display/lowhalf-format-instruction-g.pkg

#
# This just provide a very simple pretty printing function.
# It is used for visualization.
#
# -- Allen Leung 

# Compiled by:
#     src/lib/compiler/back/low/lib/visual.lib

stipulate
    package pp  =  standard_prettyprinter;                                      # standard_prettyprinter        is from   src/lib/prettyprint/big/src/standard-prettyprinter.pkg
herein

    api Format_Instruction {
        #
        package mcf:  Machcode_Form;                                            # Machcode_Form                 is from   src/lib/compiler/back/low/code/machcode-form.api

        to_string
            :
            note::Notes
            ->
            mcf::Machine_Op
            ->
            String;
    };

    # This generic is invoked (only) in:
    #     src/lib/compiler/back/low/display/machcode-controlflow-graph-viewer-g.pkg
    #     src/lib/compiler/back/low/glue/lowhalf-glue.pkg.unused

    generic package   format_instruction_g   (
        #             ====================
        #
        asm:  Machcode_Codebuffer_Pp                                            # Machcode_Codebuffer_Pp        is from   src/lib/compiler/back/low/emit/machcode-codebuffer-pp.api
    )
    : (weak)  Format_Instruction                                                # Format_Instruction            is from   src/lib/compiler/back/low/display/lowhalf-format-instruction-g.pkg
    {
        # Export to client packages:
        #       
        package mcf = asm::mcf;                                                 # "mcf"  == "Machcode_Form" (abstract machine code).

        fun to_string  an  op
            =
            strip_nl  text
            where

#               buffer =   string_outstream::make_stream_buf();
#               sss    =   string_outstream::open_string_out buffer;

#               asm_stream::with_stream  sss
#                   #
#                   (asm::make_codebuffer an).put_op
#                   op;
#
#               text   = string_outstream::get_string buffer;

                text =  pp::prettyprint_to_string [] {.
                            pp = #pp;
                            buf = asm::make_codebuffer pp an;
                            buf.put_op op;
                        };

                fun is_space ' '  =>   TRUE;
                    is_space '\t' =>   TRUE;
                    is_space _    =>   FALSE;
                end;

                text = fold_backward
                           \\ (x, "") =>  x;
                              (x,  y) =>  x + " " + y;
                           end
                           ""
                           (string::tokens is_space text);

                fun strip_nl "" =>   "";
                    #
                    strip_nl s
                        =>
                        f (size s - 1)
                        where
                            fun f (0) => "";

                                f (i) => case (string::get_byte_as_char (s, i))
                                             #
                                              '\n' => f (i - 1);
                                              ' '  => f (i - 1);
                                              _    => string::extract (s, 0, THE (i+1));
                                         esac;
                            end;
                        end;
                end;  
             end;
    };
end;