shithub: pprolog

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ref: 3f316c5c9265618fe7095cc39c4cb10909cbe468
parent: 8ef27e2fe652a8b29a8b57589863f2f2b45f9425
author: Peter Mikkelsen <[email protected]>
date: Fri Jul 16 16:09:02 EDT 2021

Implement a bit more of prolog flag predicates set_prolog_flag/2 and current_prolog_flag/2

--- a/builtins.c
+++ b/builtins.c
@@ -38,7 +38,7 @@
 BuiltinProto(builtincatch);
 BuiltinProto(builtinthrow);
 BuiltinProto(builtinsetprologflag);
-BuiltinProto(builtincurrentprologflag);
+BuiltinProto(builtincurrentprologflags);
 BuiltinProto(builtinopen);
 BuiltinProto(builtinclose);
 BuiltinProto(builtincurrentinput);
@@ -125,10 +125,10 @@
 		return builtincatch;
 	if(Match(L"throw", 1))
 		return builtinthrow;
-	if(Match(L"set_prolog_flag", 2))
+	if(Match(L"$set_prolog_flag", 2))
 		return builtinsetprologflag;
-	if(Match(L"current_prolog_flag", 2))
-		return builtincurrentprologflag;
+	if(Match(L"current_prolog_flags", 1))
+		return builtincurrentprologflags;
 	if(Match(L"open", 4))
 		return builtinopen;
 	if(Match(L"close", 2))
@@ -605,12 +605,13 @@
 }
 
 int
-builtincurrentprologflag(Term *goal, Binding **bindings, Module *module)
+builtincurrentprologflags(Term *goal, Binding **bindings, Module *module)
 {
-	USED(goal);
-	USED(bindings);
 	USED(module);
-	return 0;
+	Term *flagsandvals = goal->children;
+	Term *list = getallflags();
+	Term *realflagsandvals = mklist(list);
+	return unify(flagsandvals, realflagsandvals, bindings);
 }
 
 int
@@ -621,15 +622,7 @@
 	Term *key = goal->children;
 	Term *value = key->next;
 
-	if(key->tag == VariableTerm || value->tag == VariableTerm)
-		Throw(instantiationerror());
-
-	if(key->tag != AtomTerm)
-		Throw(typeerror(L"atom", key));
-
-	Term *error = setflag(key->text, value);
-	if(error)
-		Throw(error);
+	setflag(key->text, value);
 	return 1;
 }
 
--- a/dat.h
+++ b/dat.h
@@ -109,12 +109,47 @@
 
 /* Flags */
 enum {
+	BoundedTrue,
+	BoundedFalse,
+};
+
+enum {
+	IntegerRoundDown,
+	IntegerRoundTowardZero,
+};
+
+enum {
+	CharConversionOn,
+	CharConversionOff,
+};
+
+enum {
+	DebugOn,
+	DebugOff,
+};
+
+enum {
+	UnknownError,
+	UnknownFail,
+	UnknownWarning,
+};
+
+enum {
 	DoubleQuotesChars,
 	DoubleQuotesCodes,
 	DoubleQuotesAtom,
 };
 
+int flagbounded;
+vlong flagmaxinteger;
+vlong flagmininteger;
+int flagintegerroundingfunction;
+int flagcharconversion;
+int flagdebug;
+vlong flagmaxarity;
+int flagunknown;
 int flagdoublequotes;
+
 
 /* State of the running system */
 Choicepoint *choicestack;
--- a/flags.c
+++ b/flags.c
@@ -5,36 +5,160 @@
 #include "dat.h"
 #include "fns.h"
 
-Term *setdoublequotes(Term *);
+void setcharconversion(Term *);
+void setdebug(Term *);
+void setunknown(Term *);
+void setdoublequotes(Term *);
 
+static Rune *boundedvals[] = {
+	[BoundedTrue] = L"true",
+	[BoundedFalse] = L"false"
+};
+
+static Rune *integerroundvals[] = {
+	[IntegerRoundDown] = L"down",
+	[IntegerRoundTowardZero] = L"toward_zero"
+};
+
+static Rune *charconversionvals[] = {
+	[CharConversionOn] = L"on",
+	[CharConversionOff] = L"off"
+};
+
+static Rune *debugvals[] = {
+	[DebugOn] = L"on",
+	[DebugOff] = L"off"
+};
+
+static Rune *unknownvals[] = {
+	[UnknownError] = L"error",
+	[UnknownFail] = L"fail",
+	[UnknownWarning] = L"warning"
+};
+
+static Rune *doublequotesvals[] = {
+	[DoubleQuotesChars] = L"chars",
+	[DoubleQuotesCodes] = L"codes",
+	[DoubleQuotesAtom] = L"atom"
+};
+
 void
 initflags(void)
 {
+	uvlong zero = 0;
+
+	flagbounded = BoundedTrue;
+	flagmaxinteger = (~zero)>>1;
+	flagmininteger = flagmaxinteger+1;
+	flagintegerroundingfunction = IntegerRoundDown;
+	flagcharconversion = CharConversionOff;
+	flagdebug = DebugOff;
+	flagunknown = UnknownError;
 	flagdoublequotes = DoubleQuotesChars;
 }
 
-Term *
+void
 setflag(Rune *flag, Term *value)
 {
-	if(runestrcmp(flag, L"double_quotes") == 0)
-		return setdoublequotes(value);
-	else
-		return permissionerror(L"modify", L"flag", mkatom(flag));
+	if(runestrcmp(flag, L"char_conversion") == 0)
+		setcharconversion(value);
+	else if(runestrcmp(flag, L"debug") == 0)
+		setdebug(value);
+	else if(runestrcmp(flag, L"unknown") == 0)
+		setunknown(value);
+	else if(runestrcmp(flag, L"double_quotes") == 0)
+		setdoublequotes(value);
 }
 
 Term *
-setdoublequotes(Term *value)
+getallflags(void)
 {
-	if(value->tag != AtomTerm)
-		return typeerror(L"atom", value);
+	Term *boundedval = mkatom(boundedvals[flagbounded]);
+	Term *maxintval = mkinteger(flagmaxinteger);
+	Term *minintval = mkinteger(flagmininteger);
+	Term *roundingval = mkatom(integerroundvals[flagintegerroundingfunction]);
+	Term *charconvval = mkatom(charconversionvals[flagcharconversion]);
+	Term *debugval = mkatom(debugvals[flagdebug]);
+	Term *unknownval = mkatom(unknownvals[flagunknown]);
+	Term *doublequotesval = mkatom(doublequotesvals[flagdoublequotes]);
 
-	if(runestrcmp(value->text, L"chars") == 0)
-		flagdoublequotes = DoubleQuotesChars;
-	else if(runestrcmp(value->text, L"codes") == 0)
-		flagdoublequotes = DoubleQuotesCodes;
-	else if(runestrcmp(value->text, L"atom") == 0)
-		flagdoublequotes = DoubleQuotesAtom;
-	else
-		return domainerror(L"flag_value", value);
-	return nil;
+	Term *boundedkey = mkatom(L"bounded");
+	boundedkey->next = boundedval;
+	Term *maxintkey = mkatom(L"max_integer");
+	maxintkey->next = maxintval;
+	Term *minintkey = mkatom(L"min_integer");
+	minintkey->next = minintval;
+	Term *roundingkey = mkatom(L"integer_rounding_function");
+	roundingkey->next = roundingval;
+	Term *charconvkey = mkatom(L"character_conversion");
+	charconvkey->next = charconvval;
+	Term *debugkey = mkatom(L"debug");
+	debugkey->next = debugval;
+	Term *unknownkey = mkatom(L"unknown");
+	unknownkey->next = unknownval;
+	Term *doublequoteskey = mkatom(L"double_quotes");
+	doublequoteskey->next = doublequotesval;
+
+	Term *boundedflag = mkcompound(L"flag", 2, boundedkey);
+	Term *maxintflag = mkcompound(L"flag", 2, maxintkey);
+	Term *minintflag = mkcompound(L"flag", 2, minintkey);
+	Term *roundingflag = mkcompound(L"flag", 2, roundingkey);
+	Term *charconvflag = mkcompound(L"flag", 2, charconvkey);
+	Term *debugflag = mkcompound(L"flag", 2, debugkey);
+	Term *unknownflag = mkcompound(L"flag", 2, unknownkey);
+	Term *doublequotesflag = mkcompound(L"flag", 2, doublequoteskey);
+
+	boundedflag->next = maxintflag;
+	maxintflag->next = minintflag;
+	minintflag->next = roundingflag;
+	roundingflag->next = charconvflag;
+	charconvflag->next = debugflag;
+	debugflag->next = unknownflag;
+	unknownflag->next = doublequotesflag;
+
+	return boundedflag;
+}
+
+void
+setcharconversion(Term *value)
+{
+	int max = 2;
+	int i;
+	for(i = 0; i < max; i++){
+		if(runestrcmp(value->text, charconversionvals[i]) == 0)
+			flagcharconversion = i;
+	}
+}
+
+void
+setdebug(Term *value)
+{
+	int max = 2;
+	int i;
+	for(i = 0; i < max; i++){
+		if(runestrcmp(value->text, debugvals[i]) == 0)
+			flagdebug = i;
+	}
+}
+
+void
+setunknown(Term *value)
+{
+	int max = 3;
+	int i;
+	for(i = 0; i < max; i++){
+		if(runestrcmp(value->text, unknownvals[i]) == 0)
+			flagunknown = i;
+	}
+}
+
+void
+setdoublequotes(Term *value)
+{
+	int max = 3;
+	int i;
+	for(i = 0; i < max; i++){
+		if(runestrcmp(value->text, doublequotesvals[i]) == 0)
+			flagdoublequotes = i;
+	}
 }
\ No newline at end of file
--- a/fns.h
+++ b/fns.h
@@ -30,7 +30,8 @@
 
 /* flags.c */
 void initflags(void);
-Term *setflag(Rune *, Term *);
+void setflag(Rune *, Term *);
+Term *getallflags(void);
 
 /* error.c */
 Term *instantiationerror(void);
--- a/repl.pl
+++ b/repl.pl
@@ -52,8 +52,10 @@
 write_result([B|Bs], State) :- write_bindings([B|Bs]), write_state(State).
 
 write_bindings([]).
-write_bindings([B|Bs]) :-
-	write(B),
+write_bindings([Var = Val|Bs]) :-
+	write(Var),
+	write(' = '),
+	writeq(Val),
 	( Bs = []
 	-> true
 	; put_char(','), nl
--- a/stdlib.pl
+++ b/stdlib.pl
@@ -549,3 +549,60 @@
 nl(S) :-
 	put_char(S, '
 '). % This should really be \n
+
+% flags
+set_prolog_flag(Flag, Value) :-
+	is_nonvar(Flag),
+	is_nonvar(Value),
+	is_atom(Flag),
+	is_prolog_flag(Flag),
+	is_appropriate_flag_value(Flag, Value),
+	is_modifiable_flag(Flag),
+	'$set_prolog_flag'(Flag, Value).
+
+current_prolog_flag(Flag, Value) :-
+	is_atom_or_var(Flag),
+	( atom(Flag)
+	-> is_prolog_flag(Flag)
+	; true
+	),
+	current_prolog_flags(FlagsAndValues),
+	member(flag(Flag, Value), FlagsAndValues).
+
+is_prolog_flag(Flag) :-
+	member(Flag, 
+		[ bounded
+		, max_integer
+		, min_integer
+		, integer_rounding_function
+		, char_conversion
+		, debug
+		, max_arity
+		, unknown
+		, double_quotes]),
+	!
+	; domain_error(prolog_flag, Flag).
+
+is_modifiable_flag(Flag) :-
+	member(Flag, [char_conversion, debug, unknown, double_quotes]),
+	!
+	; permission_error(modify, flag, Flag).
+
+is_appropriate_flag_value(Flag, Value) :-
+	appropriate_flag_values(Flag, Values), 
+	member(Value, Values),
+	!
+	; domain_error(flag_value, Flag + Value).
+
+appropriate_flag_values(bounded, [true, false]).
+appropriate_flag_values(max_integer, [Val]) :-
+	current_prolog_flag(max_integer, Val).
+appropriate_flag_values(min_integer, [Val]) :-
+	current_prolog_flag(min_integer, Val).
+appropriate_flag_values(integer_rounding_function, [down, toward_zero]).
+appropriate_flag_values(char_conversion, [on, off]).
+appropriate_flag_values(debug, [on, off]).
+appropriate_flag_values(max_arity, [Val]) :-
+	current_prolog_flag(max_arity).
+appropriate_flag_values(unknown, [error, fail, warning]).
+appropriate_flag_values(double_quotes, [chars, codes, atom]).
\ No newline at end of file