Execute Brain****: Difference between revisions

===Interpreter===

===Transpiler===

Based on the interpreter. Attempts to optimise consecutive +, -, <, > and ? operations.

<lang algol68>BEGIN # Brain**** -> Algol 68 transpiler #

# a single line of Brain**** code is prompted for and read from #

# standard input, the generated code is written to standard output #

# the original code is included in the output as a comment #

# transpiles the Brain**** code in code list to Algol 68 #

PROC generate = ( STRING code list )VOID:

BEGIN

PROC emit = ( STRING code )VOID: print( ( code, newline ) );

PROC emit1 = ( STRING code )VOID:

print( ( IF need semicolon THEN ";" ELSE "" FI

, newline, indent, code

)

);

PROC next = CHAR: IF c pos > c max

THEN "$"

ELSE CHAR result = code list[ c pos ];

c pos +:= 1;

result

FI;

# address and data modes and the data space #

emit( "BEGIN" );

emit( " MODE DADDR = INT; # data address #" );

emit( " MODE DATA = INT;" );

emit( " DATA zero = 0;" );

emit( " [-255:255]DATA data; # finite data space #" );

emit( " FOR i FROM LWB data TO UPB data DO data[i] := zero OD;" );

emit( " DADDR addr := ( UPB data + LWB data ) OVER 2;" );

# actual code #

STRING indent := " ";

BOOL need semicolon := FALSE;

INT c pos := LWB code list;

INT c max = UPB code list;

CHAR c := next;

WHILE c /= "$" DO

IF c = "?"

THEN emit1( "SKIP" );

need semicolon := TRUE;

WHILE ( c := next ) = "?" DO SKIP OD

ELIF c = "<" OR c = ">"

THEN CHAR op code = c;

CHAR assign op = IF c = ">" THEN "+" ELSE "-" FI;

INT incr := 1;

WHILE ( c := next ) = op code DO incr +:= 1 OD;

emit1( "addr " + assign op + ":= " + whole( incr, 0 ) );

need semicolon := TRUE

ELIF c = "+" OR c = "-"

THEN CHAR op code = c;

INT incr := 1;

WHILE ( c := next ) = op code DO incr +:= 1 OD;

emit1( "data[ addr ] " + op code + ":= " + whole( incr, 0 ) );

need semicolon := TRUE

ELIF c = "."

THEN emit1( "print( ( REPR data[ addr ] ) )" );

need semicolon := TRUE;

c := next

ELIF c = ","

THEN emit1( "data[ addr ] := ABS read char" );

need semicolon := TRUE;

c := next

ELIF c = "["

THEN emit1( "WHILE data[ addr ] /= zero DO" );

indent +:= " ";

need semicolon := FALSE;

c := next

ELIF c = "]"

THEN need semicolon := FALSE;

indent := indent[ LWB indent + 2 : ];

emit1( "OD" );

need semicolon := TRUE;

c := next

ELSE

print( ( "Invalid op code: """, c, """", newline ) );

c := next

FI

OD;

emit( "" );

emit( "END" )

END # gen # ;

# get the code to transpile and output it as a comment at the start #

# of the code #

print( ( "CO BF> " ) );

STRING code list;

read( ( code list, newline ) );

print( ( newline, code list, newline, "CO", newline ) );

# transpile the code #

generate( code list )

END</lang>

With the following input:

<lang bf>>++++++++[<+++++++++>-]<.>>+>+>++>[-]+<[>[->+<<++++>]<<]>.+++++++..+++.>>+++++++.<<<[[-]<[-]>]<+++++++++++++++.>>.+++.------.--------.>>+.>++++.</lang>

The follwoing Algol 68 program is output:

<lang algol68>CO BF>

>++++++++[<+++++++++>-]<.>>+>+>++>[-]+<[>[->+<<++++>]<<]>.+++++++..+++.>>+++++++.<<<[[-]<[-]>]<+++++++++++++++.>>.+++.------.--------.>>+.>++++.

CO

BEGIN

MODE DADDR = INT; # data address #

MODE DATA = INT;

DATA zero = 0;

[-255:255]DATA data; # finite data space #

FOR i FROM LWB data TO UPB data DO data[i] := zero OD;

DADDR addr := ( UPB data + LWB data ) OVER 2;

addr +:= 1;

data[ addr ] +:= 8;

WHILE data[ addr ] /= zero DO

addr -:= 1;

data[ addr ] +:= 9;

addr +:= 1;

data[ addr ] -:= 1

OD;

addr -:= 1;

print( ( REPR data[ addr ] ) );

addr +:= 2;

data[ addr ] +:= 1;

addr +:= 1;

data[ addr ] +:= 1;

addr +:= 1;

data[ addr ] +:= 2;

addr +:= 1;

WHILE data[ addr ] /= zero DO

data[ addr ] -:= 1

OD;

data[ addr ] +:= 1;

addr -:= 1;

WHILE data[ addr ] /= zero DO

addr +:= 1;

WHILE data[ addr ] /= zero DO

data[ addr ] -:= 1;

addr +:= 1;

data[ addr ] +:= 1;

addr -:= 2;

data[ addr ] +:= 4;

addr +:= 1

OD;

addr -:= 2

OD;

addr +:= 1;

print( ( REPR data[ addr ] ) );

data[ addr ] +:= 7;

print( ( REPR data[ addr ] ) );

print( ( REPR data[ addr ] ) );

data[ addr ] +:= 3;

print( ( REPR data[ addr ] ) );

addr +:= 2;

data[ addr ] +:= 7;

print( ( REPR data[ addr ] ) );

addr -:= 3;

WHILE data[ addr ] /= zero DO

WHILE data[ addr ] /= zero DO

data[ addr ] -:= 1

OD;

addr -:= 1;

WHILE data[ addr ] /= zero DO

data[ addr ] -:= 1

OD;

addr +:= 1

OD;

addr -:= 1;

data[ addr ] +:= 15;

print( ( REPR data[ addr ] ) );

addr +:= 2;

print( ( REPR data[ addr ] ) );

data[ addr ] +:= 3;

print( ( REPR data[ addr ] ) );

data[ addr ] -:= 6;

print( ( REPR data[ addr ] ) );

data[ addr ] -:= 8;

print( ( REPR data[ addr ] ) );

addr +:= 2;

data[ addr ] +:= 1;

print( ( REPR data[ addr ] ) );

addr +:= 1;

data[ addr ] +:= 4;

print( ( REPR data[ addr ] ) )

END</lang>

Which when run, produces the following:

{{out}}

<pre>

Hello World!

</pre>