interpl

commit 69ad1c665bd4f7383a31bb74d8fb16c1a617c49d
parent ef83e0383499ee1b1e52d2610fa39f5ba2191d79
Author: Jan Pobrislo <ccx@te2000.cz>
Date:   Fri, 30 May 2025 15:51:49 +0000

working sexp parser

Diffstat:
M
interpreter.pl
 | 
35
++++++++++++++++++++++++++++++++++-
M
tests.pl
 | 
26
+++++++++++++++++++-------

2 files changed, 53 insertions(+), 8 deletions(-)
diff --git a/interpreter.pl b/interpreter.pl
@@ -1,8 +1,12 @@
 %% #!/usr/bin/env swipl
 :- module(interpreter,
 	[ parse_input_expression/2
+	, sexp//1
+	, sexp/4
 	]).
 :- use_module(library(debug), [assertion/1]).
+:- use_module(library(dcg/basics), [blanks//0, number//1]).
+:- use_module(library(quasi_quotations), [phrase_from_quasi_quotation/2, quasi_quotation_syntax/1]).
 :- use_module(library(pairs)).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -235,7 +239,36 @@ prolog:error_message(evaluation_error(Codes)) -->
 parse_input_expression(Codes, Expression) :-
 	phrase(sexp(Expression), Codes).
 
-sexp(_Expression) --> { false }.  % TODO
+sexp(List) --> `(`, blanks, sexp_list(List).
+sexp(Number) --> number(Number).
+sexp(Atom) -->
+	{ ground(Atom) }, !,
+	{ atom_codes(Atom, Codes) },
+	Codes.
+sexp(Atom) -->
+	{ var(Atom) }, !,
+	[Initial],
+	{ atom_start_code(Initial) },
+	atom_tail(Codes),
+	{ atom_codes(Atom, [Initial|Codes]) }.
+
+atom_tail([Code|Tail]) --> [Code], { atom_code(Code) }, !, atom_tail(Tail).
+atom_tail([]) --> { true }.
+
+atom_code(Code) :-
+	code_type(Code, graph), % non-whitespace / non-control
+	Code \= 40,  % open paren
+	Code \= 41.  % close paren
+
+atom_start_code(Code) :-
+	atom_code(Code), \+ code_type(Code, digit).
+
+sexp_list([]) --> `)`.
+sexp_list([Value|Rest]) --> sexp(Value), blanks, sexp_list(Rest).
+
+sexp(Content, _, _, Result) :-
+	phrase_from_quasi_quotation(sexp(Result), Content).
+:- quasi_quotation_syntax(sexp).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Interpreter wrapper
diff --git a/tests.pl b/tests.pl
@@ -4,37 +4,49 @@
 
 test_one_result(Template, Goal, Output) :-
 	findall(Template, Goal, Results),
+	% write(Results), nl,
 	assertion(length(Results, 1)),
 	Results = [Output].
 
+decode(Codes, Expression) :-
+	test_one_result(E, parse_input_expression(Codes, E), Expression).
+
 :- begin_tests(sexp).
 
 test(sexp_atom) :-
-	parse_input_expression(`a`, Expression),
+	decode(`a`, Expression),
 	assertion(Expression =@= a).
 
 test(sexp_atom2) :-
-	parse_input_expression(`hello-world!`, Expression),
+	decode(`hello-world!`, Expression),
 	assertion(Expression =@= 'hello-world!').
 
 test(sexp_number) :-
-	parse_input_expression(`0`, Expression),
+	decode(`0`, Expression),
 	assertion(Expression =@= 0).
 
 test(sexp_number2) :-
-	parse_input_expression(`31337`, Expression),
+	decode(`31337`, Expression),
 	assertion(Expression =@= 31337).
 
 test(sexp_list_empty) :-
-	parse_input_expression(`()`, Expression),
+	decode(`()`, Expression),
 	assertion(Expression =@= []).
 
 test(sexp_list_one_atom) :-
-	parse_input_expression(`(a)`, Expression),
+	decode(`(a)`, Expression),
 	assertion(Expression =@= [a]).
 
 test(sexp_list_one_two_atoms) :-
-	parse_input_expression(`(a)`, Expression),
+	decode(`(a b)`, Expression),
 	assertion(Expression =@= [a, b]).
 
+test(sexp_def) :-
+	decode(`(define proc (lambda (e f g) (lambda () e)))`, Expression),
+	assertion(Expression =@= [define, proc, [lambda, [e, f, g], [lambda, [], e]]]).
+
+test(sexp_qq) :-
+	Expression = {|sexp||(define proc (lambda (e f g) (lambda () e)))|},
+	assertion(Expression =@= [define, proc, [lambda, [e, f, g], [lambda, [], e]]]).
+
 :- end_tests(sexp).