Closure operator now behaves as default argument operator, documentation.

doc/script/index.txt

@@ -12,3 +12,41 @@ MSE uses a custom scripting language to add complicated behaviour to [[type:fiel
 See also:
 * [[type:index|Data types used]]
 * [[fun:index|Built in functions]]
+
+--Syntax index--
+| @123@			[[type:int|A literal number]]
+| @"stuff"@		[[type:string|A literal string]]
+| @[a,b,c]@		[[type:list|A literal list]]
+| @[a:b, c:d]@		[[type:map|A literal map]]
+| @{ expr }@		[[script:variables#Functions|Function definition]]
+| @fun(a:b, c:d)@	[[script:variables#Functions|Function call]]
+| @fun(value)@		[[script:variables#Functions|Function call with '@input@' argument]]
+| @fun@@(a:b)@		[[script:variables#Default arguments|Default arguments]]
+| @a.b@			[[script:operators|Property 'b' of 'a']]
+| @a[b]@		[[script:operators|Property 'value of b' of 'a']]
+| @-a@			[[script:operators|Negation]]
+| @a + b@		[[script:operators|Addition / concatenation]]
+| @a - b@		[[script:operators|Subtraction]]
+| @a * b@		[[script:operators|Multiplication]]
+| @a / b@		[[script:operators|Floating point division]]
+| @a div b@		[[script:operators|Integer division]]
+| @a mod b@		[[script:operators|Remainder]]
+| @not a@		[[type:boolean|Boolean not]]
+| @a and b@		[[type:boolean|Boolean conjunction]]
+| @a or b@		[[type:boolean|Boolean disjunction]]
+| @a xor b@		[[type:boolean|Boolean xor]]
+| @a == b@		[[script:operators|Comparison for equality]]
+| @a != b@		[[script:operators|Comparison for inequality]]
+| @a < b@		[[script:operators|Comparison]]
+| @a > b@		[[script:operators|Comparison]]
+| @a <= b@		[[script:operators|Comparison]]
+| @a >= b@		[[script:operators|Comparison]]
+| @a or else b@		Use @a@ unless it is an error, then use @b@ instead.
+| @min(a,b,c,...)@	[[script:operators|Smallest of the values]]
+| @max(a,b,c,...)@	[[script:operators|Largest of the values]]
+| @rgb(r,g,b)@		[[type:color|A color value]]
+| @rgba(r,g,b)@		[[type:color|A color value with transparency]]
+| @if x then y@		[[script:control structures|Conditional expresion]]
+| @if x then y else z@	[[script:control structures|Conditional expresion]]
+| @for x in list do y@	[[script:control structures|Loop over elements in a list]]
+| @for x from a to b do y@	[[script:control structures|Loop over numbers from a to b]]

doc/script/variables.txt

@@ -74,4 +74,17 @@ This can be done by first making a copy, and calling that:
 > to_upper("xyz") == "upper case: XYZ"
 Note that @real_to_upper@ is called without extra parameters, the @input@ variable is still set from the outer call to the new @to_upper@ itself.
 
+--Default arguments--
+It is possible to declare default arguments for functions using the @@@@ operator.
+> function := { "argument was: " + arg }@(arg:"default")
+If this function is called without the @arg@ argument, then the default value @default@ is used instead.
+For example:
+> function()                      == "argument was: default"
+> function(arg: "something else") == "argument was: something else"
+For determining whether the argument is set only explicit arguments count, not everything in scope, so
+> arg := "something else"
+> function()                      == "argument was: default"
+
+Defaults are evaluated at the time the @@@@ operator is evaluated, so they can be used to simulate static scoping.
+
 <div style="text-align:right;">next: <a href="control_structures">Control structures &rarr;</a></div>

src/data/action/keyword.cpp

@@ -177,20 +177,20 @@ void KeywordReminderTextValue::highlight(const String& code, const vector<Script
 }
 
 bool KeywordReminderTextValue::checkScript(const ScriptP& script) {
-	Context& ctx = set.cards.empty() ? set.getContext() : set.getContext(set.cards.front());
-	size_t scope = ctx.openScope();
 	try {
+		Context& ctx = set.cards.empty() ? set.getContext() : set.getContext(set.cards.front());
+		LocalScope scope(ctx);
 		for (size_t i = 0 ; i < keyword.parameters.size() ; ++i) {
 			String param = String(_("param")) << (int)(i+1);
 			ctx.setVariable(param, to_script(param));
 		}
 		script->eval(ctx);
 		errors.clear();
+		return true;
 	} catch (const Error& e) {
 		errors = e.what();
+		return false;
 	}
-	ctx.closeScope(scope);
-	return errors.empty();
 }
 
 // ----------------------------------------------------------------------------- : Changing keywords : mode

src/script/context.cpp

@@ -12,6 +12,8 @@
 #include <util/error.hpp>
 #include <iostream>
 
+DECLARE_TYPEOF_COLLECTION(pair<Variable COMMA ScriptValueP>);
+
 // ----------------------------------------------------------------------------- : Context
 
 Context::Context()
@@ -34,6 +36,10 @@ void instrQuaternary(QuaternaryInstructionType i, ScriptValueP& a, const ScriptV
 
 
 ScriptValueP Context::eval(const Script& script, bool useScope) {
+	if (level > 500) {
+		throw ScriptError(_("Stack overflow"));
+	}
+	
 	size_t stack_size = stack.size();
 	size_t scope = useScope ? openScope() : 0;
 	try {
@@ -140,7 +146,7 @@ ScriptValueP Context::eval(const Script& script, bool useScope) {
 				
 				// Closure object
 				case I_CLOSURE: {
-					makeClosure(i.data);
+					makeClosure(i.data, instr);
 					break;
 				}
 				
@@ -221,6 +227,10 @@ ScriptValueP Context::getVariable(Variable var) {
 	if (variables[var].value) return variables[var].value;
 	throw ScriptError(_("Variable not set: ") + variable_to_string(var));
 }
+int Context::getVariableScope(Variable var) {
+	if (variables[var].value) return level - variables[var].level;
+	else                      return -1;
+}
 
 
 size_t Context::openScope() {
@@ -259,6 +269,62 @@ void instrUnary  (UnaryInstructionType   i, ScriptValueP& a) {
 	}
 }
 
+// ----------------------------------------------------------------------------- : Function composition
+
+/// Composition of two functions
+class ScriptCompose : public ScriptValue {
+  public:
+	ScriptCompose(ScriptValueP a, ScriptValueP b) : a(a), b(b) {}
+	
+	virtual ScriptType type() const { return SCRIPT_FUNCTION; }
+	virtual String typeName() const { return _("function composition"); }
+	virtual ScriptValueP eval(Context& ctx) const {
+		ctx.setVariable(SCRIPT_VAR_input, a->eval(ctx));
+		return b->eval(ctx);
+	}
+	virtual ScriptValueP dependencies(Context& ctx, const Dependency& dep) const {
+		ctx.setVariable(SCRIPT_VAR_input, a->dependencies(ctx, dep));
+		return b->dependencies(ctx, dep);
+	}
+  private:
+	ScriptValueP a,b;
+};
+
+// ----------------------------------------------------------------------------- : Closures
+
+/// A closure around a function
+class ScriptClosure : public ScriptValue {
+  public:
+	ScriptClosure(ScriptValueP fun) : fun(fun) {}
+	
+	/// Add a binding
+	void bind(Variable v, const ScriptValueP& value) {
+		bindings.push_back(make_pair(v,value));
+	}
+	/// Apply the bindings
+	void applyBindings(Context& ctx) const {
+		FOR_EACH_CONST(b, bindings) {
+			if (ctx.getVariableScope(b.first) != 0) {
+				ctx.setVariable(b.first, b.second);
+			}
+		}
+	}
+	
+	virtual ScriptType type() const { return SCRIPT_FUNCTION; }
+	virtual String typeName() const { return _("function closure"); }
+	virtual ScriptValueP eval(Context& ctx) const {
+		applyBindings(ctx);
+		return fun->eval(ctx);
+	}
+	virtual ScriptValueP dependencies(Context& ctx, const Dependency& dep) const {
+		applyBindings(ctx);
+		return fun->dependencies(ctx, dep);
+	}
+  private:
+	ScriptValueP                         fun;
+	vector<pair<Variable,ScriptValueP> > bindings;
+};
+
 // ----------------------------------------------------------------------------- : Simple instructions : binary
 
 // operator on ints
@@ -284,24 +350,6 @@ void instrUnary  (UnaryInstructionType   i, ScriptValueP& a) {
 	}															\
 	break
 
-/// Composition of two functions
-class ScriptCompose : public ScriptValue {
-  public:
-	ScriptCompose(ScriptValueP a, ScriptValueP b) : a(a), b(b) {}
-	
-	virtual ScriptType type() const { return SCRIPT_FUNCTION; }
-	virtual String typeName() const { return _("function composition"); }
-	virtual ScriptValueP eval(Context& ctx) const {
-		ctx.setVariable(SCRIPT_VAR_input, a->eval(ctx));
-		return b->eval(ctx);
-	}
-	virtual ScriptValueP dependencies(Context& ctx, const Dependency& dep) const {
-		ctx.setVariable(SCRIPT_VAR_input, a->dependencies(ctx, dep));
-		return b->dependencies(ctx, dep);
-	}
-  private:
-	ScriptValueP a,b;
-};
 
 void instrBinary (BinaryInstructionType  i, ScriptValueP& a, const ScriptValueP& b) {
 	switch (i) {
@@ -408,9 +456,14 @@ void Context::makeObject(size_t n) {
 	stack.push_back(ret);
 }
 
-void Context::makeClosure(size_t n) {
-	//intrusive_ptr<ScriptClosure> ret(new ScriptClosure());
-	// TODO
-	//stack.push_back(ret);
-	throw InternalError(_("TODO: makeClosure"));
+void Context::makeClosure(size_t n, const Instruction*& instr) {
+	intrusive_ptr<ScriptClosure> closure(new ScriptClosure(stack[stack.size() - n - 1]));
+	for (size_t j = 0 ; j < n ; ++j) {
+		closure->bind((Variable)instr[n - j - 1].data, stack.back());
+		stack.pop_back();
+	}
+	// skip arguments
+	instr += n;
+	// set value
+	stack.back() = closure;
 }

src/script/context.hpp

@@ -62,12 +62,20 @@ class Context {
 	ScriptValueP getVariable(Variable var);
 	/// Get the value of a variable, returns ScriptValue() if it is not set
 	inline ScriptValueP getVariableOpt(Variable var) { return variables[var].value; }
+	/// In what scope was the variable set?
+	/** Returns 0 for the current scope and >0 for outer scopes.
+	 *  Returns -1 if the varible is not set
+	 */
+	int getVariableScope(Variable var);
+	
+  private:
 	
 	/// Open a new scope
 	/** returns the number of shadowed binding before that scope */
 	size_t openScope();
 	/// Close a scope, must be passed a value from openScope
 	void closeScope(size_t scope);
+	friend class LocalScope;
 	
   public:// public for FOR_EACH
 	/// Record of a variable
@@ -102,7 +110,7 @@ class Context {
 	/// Make an object with n elements, popping 2n values from the stack, and push it onto the stack
 	void makeObject(size_t n);
 	/// Make a closure with n arguments
-	void makeClosure(size_t n);
+	void makeClosure(size_t n, const Instruction*& instr);
 };
 
 /// A class that creates a local scope

src/script/dependency.cpp

@@ -250,9 +250,9 @@ ScriptValueP Context::dependencies(const Dependency& dep, const Script& script)
 					break;
 				}
 				
-				// Closure object
+				// Closure object (as normal)
 				case I_CLOSURE: {
-					makeClosure(i.data);
+					makeClosure(i.data, instr);
 					break;
 				}
 				

src/script/parser.cpp

@@ -104,8 +104,8 @@ class TokenIterator {
 	vector<ScriptParseError>& errors;
 	/// Add an error message
 	void add_error(const String& message);
-	/// Expected some token instead of what was found
-	void expected(const String& exp);
+	/// Expected some token instead of what was found, possibly a matching opening bracket is known
+	void expected(const String& exp, const Token* opening = nullptr);
 };
 
 // ----------------------------------------------------------------------------- : Characters
@@ -293,25 +293,28 @@ void TokenIterator::readStringToken() {
 	}
 }
 
-
-void TokenIterator::add_error(const String& message) {
-	if (!errors.empty() && errors.back().start == pos) return; // already an error here
-	// find line number
+int line_number(size_t pos, const String& input) {
 	int line = 1;
 	for (size_t i = 0 ; i < input.size() && i < pos ; ++i) {
 		if (input.GetChar(i) == _('\n')) line++;
 	}
-	errors.push_back(ScriptParseError(pos, line, filename, message));
+	return line;
+}
+
+void TokenIterator::add_error(const String& message) {
+	if (!errors.empty() && errors.back().start == pos) return; // already an error here
+	// add error message
+	errors.push_back(ScriptParseError(pos, line_number(pos,input), filename, message));
 }
-void TokenIterator::expected(const String& expected) {
+void TokenIterator::expected(const String& expected, const Token* opening) {
 	size_t error_pos = peek(0).pos;
 	if (!errors.empty() && errors.back().start == pos) return; // already an error here
-	// find line number
-	int line = 1;
-	for (size_t i = 0 ; i < input.size() && i < error_pos ; ++i) {
-		if (input.GetChar(i) == _('\n')) line++;
+	// add error message
+	if (opening) {
+		errors.push_back(ScriptParseError(opening->pos, error_pos, line_number(opening->pos,input), filename, opening->value, expected, peek(0).value));
+	} else {
+		errors.push_back(ScriptParseError(error_pos, line_number(error_pos,input), filename, expected, peek(0).value));
 	}
-	errors.push_back(ScriptParseError(error_pos, line, filename, expected, peek(0).value));
 }
 
 
@@ -385,12 +388,12 @@ ScriptP parse(const String& s, Packaged* package, bool string_mode) {
 
 
 // Expect a token, adds an error if it is not found
-bool expectToken(TokenIterator& input, const Char* expect, const Char* name_in_error = nullptr) {
+bool expectToken(TokenIterator& input, const Char* expect, const Token* opening = nullptr, const Char* name_in_error = nullptr) {
 	Token token = input.read();
 	if (token == expect) {
 		return true;
 	} else {
-		input.expected(name_in_error ? name_in_error : expect);
+		input.expected(name_in_error ? name_in_error : expect, opening);
 		return false;
 	}
 }
@@ -398,16 +401,16 @@ bool expectToken(TokenIterator& input, const Char* expect, const Char* name_in_e
 void parseExpr(TokenIterator& input, Script& script, Precedence minPrec) {
 	// usually loop only once, unless we encounter newlines
 	while (true) {
-		const Token& token = input.read();
+		Token token = input.read();
 		if (token == _("(")) {
 			// Parentheses = grouping for precedence of expressions
 			parseOper(input, script, PREC_ALL);
-			expectToken(input, _(")"));
+			expectToken(input, _(")"), &token);
 		} else if (token == _("{")) {
 			// {} = function block. Parse a new Script
 			intrusive_ptr<Script> subScript(new Script);
 			parseOper(input, *subScript, PREC_ALL);
-			expectToken(input, _("}"));
+			expectToken(input, _("}"), &token);
 			script.addInstruction(I_PUSH_CONST, subScript);
 		} else if (token == _("[")) {
 			// [] = list or map literal
@@ -432,7 +435,7 @@ void parseExpr(TokenIterator& input, Script& script, Precedence minPrec) {
 					t = input.peek();
 				}
 			}
-			expectToken(input, _("]"));
+			expectToken(input, _("]"), &token);
 			script.addInstruction(I_MAKE_OBJECT, count);
 		} else if (minPrec <= PREC_UNARY && token == _("-")) {
 			parseOper(input, script, PREC_UNARY, I_UNARY, I_NEGATE); // unary negation
@@ -538,7 +541,7 @@ void parseExpr(TokenIterator& input, Script& script, Precedence minPrec) {
 					parseOper(input, script, PREC_ALL); // second, third, etc.
 					script.addInstruction(I_BINARY, op);
 				}
-				expectToken(input, _(")"));
+				expectToken(input, _(")"), &token);
 			} else {
 				// variable
 				Variable var = string_to_variable(token.value);
@@ -572,7 +575,7 @@ void parseOper(TokenIterator& input, Script& script, Precedence minPrec, Instruc
 	// EBNF:                    expr = expr | expr oper expr
 	// without left recursion:  expr = expr (oper expr)*
 	while (true) {
-		const Token& token = input.read();
+		Token token = input.read();
 		if (token != TOK_OPER && token != TOK_NAME && token!=TOK_LPAREN &&
 		    !((token == TOK_STRING || token == TOK_INT || token == TOK_DOUBLE) && minPrec <= PREC_NEWLINE && token.newline)) {
 			// not an operator-like token
@@ -646,11 +649,12 @@ void parseOper(TokenIterator& input, Script& script, Precedence minPrec, Instruc
 			} else {
 				script.addInstruction(I_BINARY, I_MEMBER);
 			}
-			expectToken(input, _("]"));
+			expectToken(input, _("]"), &token);
 		} else if (minPrec <= PREC_FUN && token==_("(")) {
 			// function call, read arguments
 			vector<Variable> arguments;
 			parseCallArguments(input, script, arguments);
+			expectToken(input, _(")"), &token);
 			// generate instruction
 			script.addInstruction(I_CALL, (unsigned int)arguments.size());
 			FOR_EACH(arg,arguments) {
@@ -658,9 +662,10 @@ void parseOper(TokenIterator& input, Script& script, Precedence minPrec, Instruc
 			}
 		} else if (minPrec <= PREC_FUN && token==_("@")) {
 			// closure call, read arguments
-			expectToken(input, _("("));
 			vector<Variable> arguments;
+			expectToken(input, _("("));
 			parseCallArguments(input, script, arguments);
+			expectToken(input, _(")"), &token);
 			// generate instruction
 			script.addInstruction(I_CLOSURE, (unsigned int)arguments.size());
 			FOR_EACH(arg,arguments) {
@@ -676,7 +681,7 @@ void parseOper(TokenIterator& input, Script& script, Precedence minPrec, Instruc
 			} else {
 				parseOper(input, script, PREC_ALL, I_BINARY, I_ADD);	// e
 			}
-			if (expectToken(input, _("}\""), _("}"))) {
+			if (expectToken(input, _("}\""), &token, _("}"))) {
 				parseOper(input, script, PREC_NONE);					// y
 				// optimize: e + ""  -> e
 				i = script.getInstructions().back();
@@ -724,5 +729,4 @@ void parseCallArguments(TokenIterator& input, Script& script, vector<Variable>&
 			t = input.peek();
 		}
 	}
-	expectToken(input, _(")"));
 }

src/util/error.cpp

@@ -33,6 +33,10 @@ ScriptParseError::ScriptParseError(size_t pos, int line, const String& filename,
 	: ParseError(_("Expected '") + exp + _("' instead of '") + found + _("'"))
 	, start(pos), end(pos + found.size()), line(line), filename(filename)
 {}
+ScriptParseError::ScriptParseError(size_t pos1, size_t pos2, int line, const String& filename, const String& open, const String& close, const String& found)
+	: ParseError(_("Expected closing '") + close + _("' for this '") + open + _("' instead of '") + found + _("'"))
+	, start(pos1), end(pos2 + found.size()), line(line), filename(filename)
+{}
 String ScriptParseError::what() const {
 	return String(_("(")) << (int)start << _("): ") << Error::what();
 }

src/util/error.hpp

@@ -83,6 +83,7 @@ class ScriptParseError : public ParseError {
   public:
 	ScriptParseError(size_t pos, int line, const String& filename, const String& str);
 	ScriptParseError(size_t pos, int line, const String& filename, const String& expected, const String& found);
+	ScriptParseError(size_t pos1, size_t pos2, int line, const String& filename, const String& open, const String& close, const String& found);
 	/// Position of the error
 	size_t start, end;
 	/// Line number of the error (the first line is 1)

tools/website/drupal/mse-drupal-modules/autoformat.inc

@@ -256,14 +256,15 @@ function autoformat__table($rows) {
 function autoformat__line($line) {
 	$line = preg_replace("/'''(.*?)'''/",  "<strong>\\1</strong>", $line);
 	$line = preg_replace("/''(.*?)''/",    "<em>\\1</em>", $line);
-	$line = preg_replace_callback("/@(.*?)@/", "autoformat__code", $line);
+	$line = preg_replace_callback("/@(([^@]|@@)*)@/", "autoformat__code", $line);
 	$line = preg_replace_callback("/\[\[(.*?)\|(.*?)]]/", "autoformat__link_s", $line);
 	$line = preg_replace_callback("/\[\[(.*?)]](s?)/", "autoformat__link", $line);
 	return $line;
 }
 
 function autoformat__code($matches) {
-	return '<tt>' . syntax_highlight(htmlspecialchars($matches[1])) . '</tt>';
+	$code = str_replace('@@','@',$matches[1]);
+	return '<tt>' . syntax_highlight(htmlspecialchars($code)) . '</tt>';
 }
 
 function autoformat__link($matches) {

tools/website/drupal/mse-drupal-modules/highlight.inc

@@ -131,7 +131,7 @@ function highlight_script($code) {
 	while(strlen($code)) {
 		if (preg_match("@^<[^>]+>@",$code, $matches)) {
 			$ret .= $matches[0]; // plain tag
-		} else if (preg_match("@^(if|then|else|for( each)?|in(?= )|do|div|mod|and|or|xor|not|rgb|rgba|from|to)\b(?!:)@",$code, $matches)) {
+		} else if (preg_match("@^(if|then|else|for( each)?|in(?= )|do|div|mod|and|or|xor|not|rgb|rgba|from|to|min|max)\b(?!:)@",$code, $matches)) {
 			$ret .= "<span class='hl-kw'>" . $matches[0] . "</span>";
 		} else if (preg_match("@^(include file:)(.*)@",$code, $matches)) {
 			$ret .= "<span class='hl-key'>" . $matches[1] . "</span>" . $matches[2];
@@ -150,7 +150,7 @@ function highlight_script($code) {
 			if ($matches[2] == '{') $string .= 's';
 		} else if (preg_match("@^\\#.*@",$code, $matches)) {
 			$ret .= "<span class='hl-comment'>" . $matches[0] . "</span>";
-		} else if (preg_match("@^([-+*/=!.]|&lt;|&gt;)+|^:=@",$code, $matches)) {
+		} else if (preg_match("@^([-+*/=!.\@]|&lt;|&gt;)+|^:=@",$code, $matches)) {
 			$ret .= "<span class='hl-op'>" . $matches[0] . "</span>";
 		} else if (preg_match("@^([}]|[\\(\\)\\[\\]{,]+)@",$code, $matches)) {
 			$ret .= "<span class='hl-paren'>" . $matches[0] . "</span>";