Everywhere: Add docstring support

lisp/load.bl

@@ -1,9 +1,11 @@
 
-(defn load-file [filename]
-  (eval (read-string (str "(do " (slurp filename) "\nnil)"))))
+(defn load-file [file]
+  "Load the Lisp file named FILE."
+  (eval (read-string (str "(do " (slurp file) "\nnil)"))))
 
-(defn load [filename]
-  (eval (read-string (str "(let* [] (do " (slurp filename) "))"))))
+(defn load [file]
+  "Load the Lisp file named FILE."
+  (eval (read-string (str "(let* [] (do " (slurp file) "))"))))
 
 ;; Local Variables:
 ;; eval: (emacs-lisp-mode)

lisp/other.bl

@@ -1,5 +1,5 @@
 
-(def! *host-language* "C++")
+(def *host-language* "C++")
 
 ;; Local Variables:
 ;; eval: (emacs-lisp-mode)

lisp/predicate.bl

@@ -1,6 +1,7 @@
 
-(defn not [cond]
-  (if cond false true))
+(defn not [object]
+  "Return true if OBJECT is nil or false, and return false otherwise."
+  (if object false true))
 
 ;; Local Variables:
 ;; eval: (emacs-lisp-mode)

src/ast.cpp

@@ -225,8 +225,10 @@ Callable::Callable(ValuePtr meta)
 
 // -----------------------------------------
 
-Function::Function(const std::string& name, FunctionType function)
+Function::Function(std::string_view name, std::string_view signature, std::string_view documentation, FunctionType function)
 	: m_name(name)
+	, m_signature(signature)
+	, m_documentation(documentation)
 	, m_function(function)
 {
 }

src/ast.h

@@ -332,11 +332,13 @@ using FunctionType = std::function<ValuePtr(ValueVectorConstIt, ValueVectorConst
 
 class Function final : public Callable {
 public:
-	Function(const std::string& name, FunctionType function);
+	Function(std::string_view name, std::string_view signature, std::string_view documentation, FunctionType function);
 	Function(const Function& that, ValuePtr meta);
 	virtual ~Function() = default;
 
-	const std::string& name() const { return m_name; }
+	std::string_view name() const { return m_name; }
+	std::string_view signature() const { return m_signature; }
+	std::string_view documentation() const { return m_documentation; }
 	FunctionType function() const { return m_function; }
 
 	WITH_META(Function);
@@ -344,7 +346,9 @@ public:
 private:
 	virtual bool isFunction() const override { return true; }
 
-	const std::string m_name;
+	std::string_view m_name;
+	std::string_view m_signature;
+	std::string_view m_documentation;
 	const FunctionType m_function;
 };
 

src/env/environment.cpp

@@ -18,7 +18,7 @@
 
 namespace blaze {
 
-std::unordered_map<std::string, FunctionType> Environment::s_functions;
+std::vector<FunctionParts> Environment::s_function_parts;
 std::vector<std::string> Environment::s_lambdas;
 
 EnvironmentPtr Environment::create()
@@ -118,15 +118,20 @@ void Environment::loadFunctions()
 	}
 }
 
-void Environment::registerFunction(const std::string& name, FunctionType function)
+void Environment::registerFunction(FunctionParts function_parts)
 {
-	s_functions.insert_or_assign(name, function);
+	s_function_parts.push_back(function_parts);
 }
 
 void Environment::installFunctions(EnvironmentPtr env)
 {
-	for (const auto& [name, function] : s_functions) {
-		env->set(name, makePtr<Function>(name, function));
+	for (const auto& function_parts : s_function_parts) {
+		env->set(std::string(function_parts.name),
+		         makePtr<Function>(
+					 function_parts.name,
+					 function_parts.signature,
+					 function_parts.documentation,
+					 function_parts.function));
 	}
 	for (const auto& lambda : s_lambdas) {
 		// Ensure all s-exprs are run with (do)

src/env/environment.h

@@ -16,6 +16,14 @@
 
 namespace blaze {
 
+// All of these combined become a Function in the Environment
+struct FunctionParts {
+	std::string_view name;
+	std::string_view signature;
+	std::string_view documentation;
+	FunctionType function;
+};
+
 class Environment {
 public:
 	virtual ~Environment() = default;
@@ -26,7 +34,7 @@ public:
 	static EnvironmentPtr create(const ValuePtr lambda, ValueVector&& arguments);
 
 	static void loadFunctions();
-	static void registerFunction(const std::string& name, FunctionType function);
+	static void registerFunction(FunctionParts function_parts);
 	static void installFunctions(EnvironmentPtr env);
 
 	bool exists(const std::string& symbol);
@@ -53,7 +61,7 @@ private:
 	EnvironmentPtr m_outer { nullptr };
 	std::unordered_map<std::string, ValuePtr> m_values;
 
-	static std::unordered_map<std::string, FunctionType> s_functions;
+	static std::vector<FunctionParts> s_function_parts;
 	static std::vector<std::string> s_lambdas;
 };
 

src/env/functions/collection-access.cpp

@@ -21,6 +21,8 @@ void Environment::loadCollectionAccess()
 	// (count {:foo 2 :bar 3}) -> 2
 	ADD_FUNCTION(
 		"count",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("count", SIZE(), 1);
 
@@ -48,6 +50,8 @@ void Environment::loadCollectionAccess()
 	// (first (list 1 2 3)) -> 1
 	ADD_FUNCTION(
 		"first",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("first", SIZE(), 1);
 
@@ -64,6 +68,8 @@ void Environment::loadCollectionAccess()
 	// (nth (list 1 2 3) 0) -> 1
 	ADD_FUNCTION(
 		"nth",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("nth", SIZE(), 2);
 
@@ -83,6 +89,8 @@ void Environment::loadCollectionAccess()
 	// (rest (list 1 2 3)) -> (2 3)
 	ADD_FUNCTION(
 		"rest",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("rest", SIZE(), 1);
 
@@ -101,6 +109,8 @@ void Environment::loadCollectionAccess()
 	// (get {:kw "value"} :kw) -> "value"
 	ADD_FUNCTION(
 		"get",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("get", SIZE(), 1);
 
@@ -123,6 +133,8 @@ void Environment::loadCollectionAccess()
 	// (keys {"foo" 3 :bar 5}) -> ("foo" :bar)
 	ADD_FUNCTION(
 		"keys",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("keys", SIZE(), 1);
 
@@ -149,6 +161,8 @@ void Environment::loadCollectionAccess()
 	// (vals {"foo" 3 :bar 5}) -> (3 5)
 	ADD_FUNCTION(
 		"vals",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("vals", SIZE(), 1);
 

src/env/functions/collection-constructor.cpp

@@ -19,6 +19,8 @@ void Environment::loadCollectionConstructor()
 	// (list 1 2) -> (1 2)
 	ADD_FUNCTION(
 		"list",
+		"",
+		"",
 		{
 			return makePtr<List>(begin, end);
 		});
@@ -26,6 +28,8 @@ void Environment::loadCollectionConstructor()
 	// (make-list 4 nil) -> (nil nil nil nil)
 	ADD_FUNCTION(
 		"make-list",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("make-list", SIZE(), 2);
 
@@ -80,6 +84,8 @@ void Environment::loadCollectionConstructor()
 	// (vec (list 1 2 3))
 	ADD_FUNCTION(
 		"vec",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("vec", SIZE(), 1);
 
@@ -95,6 +101,8 @@ void Environment::loadCollectionConstructor()
 	// (vector 1 2 3) -> [1 2 3]
 	ADD_FUNCTION(
 		"vector",
+		"",
+		"",
 		{
 			auto result = makePtr<Vector>();
 
@@ -106,6 +114,8 @@ void Environment::loadCollectionConstructor()
 	// (hash-map "foo" 5 :bar 10) -> {"foo" 5 :bar 10}
 	ADD_FUNCTION(
 		"hash-map",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_EVEN("hash-map", SIZE());
 

src/env/functions/collection-modify.cpp

@@ -21,6 +21,8 @@ void Environment::loadCollectionModify()
 	// (apply + 1 2 (list 3 4)) -> (+ 1 2 3 4) -> 10
 	ADD_FUNCTION(
 		"apply",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("apply", SIZE(), 2);
 
@@ -54,6 +56,8 @@ void Environment::loadCollectionModify()
 	// (cons 1 (list 2 3))
 	ADD_FUNCTION(
 		"cons",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("cons", SIZE(), 2);
 
@@ -73,6 +77,8 @@ void Environment::loadCollectionModify()
 	// (concat (list 1) (list 2 3)) -> (1 2 3)
 	ADD_FUNCTION(
 		"concat",
+		"",
+		"",
 		{
 			size_t count = 0;
 			for (auto it = begin; it != end; ++it) {
@@ -95,6 +101,8 @@ void Environment::loadCollectionModify()
 	// (conj [1 2 3] 4 5 6)  -> [1 2 3 4 5 6]
 	ADD_FUNCTION(
 		"conj",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("conj", SIZE(), 1);
 
@@ -123,6 +131,8 @@ void Environment::loadCollectionModify()
 	// (map (fn* (x) (* x 2)) (list 1 2 3)) -> (2 4 6)
 	ADD_FUNCTION(
 		"map",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("map", SIZE(), 2);
 
@@ -152,6 +162,8 @@ void Environment::loadCollectionModify()
 	// (set-nth (list 1 2 3) 1 "foo") -> (1 "foo" 3)
 	ADD_FUNCTION(
 		"set-nth",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("set-nth-element", SIZE(), 3);
 
@@ -180,6 +192,8 @@ void Environment::loadCollectionModify()
 	// (seq "foo")    -> ("f" "o" "o")
 	ADD_FUNCTION(
 		"seq",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("seq", SIZE(), 1);
 
@@ -230,6 +244,8 @@ void Environment::loadCollectionModify()
 	// (assoc {:a 1 :b 2} :a 3 :c 1) -> {:a 3 :b 2 :c 1}
 	ADD_FUNCTION(
 		"assoc",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("assoc", SIZE(), 1);
 
@@ -250,6 +266,8 @@ void Environment::loadCollectionModify()
 	// (dissoc {:a 1 :b 2 :c 3} :a :c :d) -> {:b 2}
 	ADD_FUNCTION(
 		"dissoc",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("dissoc", SIZE(), 1);
 

src/env/functions/compare.cpp

@@ -40,10 +40,10 @@ void Environment::loadCompare()
 		return makePtr<Constant>((result) ? Constant::True : Constant::False); \
 	}
 
-	ADD_FUNCTION("<", NUMBER_COMPARE(<));
-	ADD_FUNCTION("<=", NUMBER_COMPARE(<=));
-	ADD_FUNCTION(">", NUMBER_COMPARE(>));
-	ADD_FUNCTION(">=", NUMBER_COMPARE(>=));
+	ADD_FUNCTION("<", "", "", NUMBER_COMPARE(<));
+	ADD_FUNCTION("<=", "", "", NUMBER_COMPARE(<=));
+	ADD_FUNCTION(">", "", "", NUMBER_COMPARE(>));
+	ADD_FUNCTION(">=", "", "", NUMBER_COMPARE(>=));
 
 	// -----------------------------------------
 
@@ -51,6 +51,8 @@ void Environment::loadCompare()
 	// (= "foo" "foo") -> true
 	ADD_FUNCTION(
 		"=",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("=", SIZE(), 2);
 

src/env/functions/convert.cpp

@@ -18,6 +18,8 @@ void Environment::loadConvert()
 	// (number-to-string 123) -> "123"
 	ADD_FUNCTION(
 		"number-to-string",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("number-to-string", SIZE(), 1);
 
@@ -37,6 +39,8 @@ void Environment::loadConvert()
 	// (string-to-char "123") -> 49
 	ADD_FUNCTION(
 		"string-to-char",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("string-to-char", SIZE(), 1);
 
@@ -49,6 +53,8 @@ void Environment::loadConvert()
 	// (string-to-number "123") -> 123
 	ADD_FUNCTION(
 		"string-to-number",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("string-to-number", SIZE(), 1);
 
@@ -83,14 +89,16 @@ void Environment::loadConvert()
 
 	// (string-to-list "foo")   -> (102 111 111)
 	// (string-to-vector "foo") -> [102 111 111]
-	ADD_FUNCTION("string-to-list", STRING_TO_COLLECTION("string-to-list", List));
-	ADD_FUNCTION("string-to-vector", STRING_TO_COLLECTION("string-to-vector", Vector));
+	ADD_FUNCTION("string-to-list", "", "", STRING_TO_COLLECTION("string-to-list", List));
+	ADD_FUNCTION("string-to-vector", "", "", STRING_TO_COLLECTION("string-to-vector", Vector));
 
 	// -------------------------------------
 
 	// (symbol "foo")  -> foo
 	ADD_FUNCTION(
 		"symbol",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("symbol", SIZE(), 1);
 
@@ -107,6 +115,8 @@ void Environment::loadConvert()
 	// (keyword 123)   -> :123
 	ADD_FUNCTION(
 		"keyword",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("keyword", SIZE(), 1);
 

src/env/functions/format.cpp

@@ -34,8 +34,8 @@ void Environment::loadFormat()
 		return makePtr<String>(result);                                               \
 	}
 
-	ADD_FUNCTION("str", PRINTER_STRING(false, ""));
-	ADD_FUNCTION("pr-str", PRINTER_STRING(true, " "));
+	ADD_FUNCTION("str", "", "", PRINTER_STRING(false, ""));
+	ADD_FUNCTION("pr-str", "", "", PRINTER_STRING(true, " "));
 
 #define PRINTER_PRINT(print_readably)                                    \
 	{                                                                    \
@@ -52,8 +52,8 @@ void Environment::loadFormat()
 		return makePtr<Constant>();                                      \
 	}
 
-	ADD_FUNCTION("prn", PRINTER_PRINT(true));
-	ADD_FUNCTION("println", PRINTER_PRINT(false));
+	ADD_FUNCTION("prn", "", "", PRINTER_PRINT(true));
+	ADD_FUNCTION("println", "", "", PRINTER_PRINT(false));
 }
 
 } // namespace blaze

src/env/functions/meta.cpp

@@ -17,6 +17,8 @@ void Environment::loadMeta()
 	// (meta [1 2 3])
 	ADD_FUNCTION(
 		"meta",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("meta", SIZE(), 1);
 
@@ -36,6 +38,8 @@ void Environment::loadMeta()
 	// (with-meta [1 2 3] "some metadata")
 	ADD_FUNCTION(
 		"with-meta",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("with-meta", SIZE(), 2);
 

src/env/functions/mutable.cpp

@@ -20,6 +20,8 @@ void Environment::loadMutable()
 	// (atom 1)
 	ADD_FUNCTION(
 		"atom",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("atom", SIZE(), 1);
 
@@ -29,6 +31,8 @@ void Environment::loadMutable()
 	// (deref myatom)
 	ADD_FUNCTION(
 		"deref",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("deref", SIZE(), 1);
 
@@ -40,6 +44,8 @@ void Environment::loadMutable()
 	// (reset! myatom 2)
 	ADD_FUNCTION(
 		"reset!",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("reset!", SIZE(), 2);
 
@@ -54,6 +60,8 @@ void Environment::loadMutable()
 	// (swap! myatom (fn* [x y] (+ 1 x y)) 2) -> (deref (def! myatom (atom ((fn* [x y] (+ 1 x y)) (deref myatom) 2))))
 	ADD_FUNCTION(
 		"swap!",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("swap!", SIZE(), 2);
 

src/env/functions/operators.cpp

@@ -16,6 +16,8 @@ void Environment::loadOperators()
 {
 	ADD_FUNCTION(
 		"+",
+		"number...",
+		"Return the sum of any amount of arguments, where NUMBER is of type number.",
 		{
 			int64_t result = 0;
 
@@ -29,6 +31,11 @@ void Environment::loadOperators()
 
 	ADD_FUNCTION(
 		"-",
+		"[number] subtract...",
+		R"(Negate NUMBER or SUBTRACT numbers and return the result.
+
+With one arg, negates it. With more than one arg,
+subtracts all but the first from the first.)",
 		{
 			size_t length = SIZE();
 			if (length == 0) {
@@ -54,6 +61,8 @@ void Environment::loadOperators()
 
 	ADD_FUNCTION(
 		"*",
+		"",
+		"",
 		{
 			int64_t result = 1;
 
@@ -67,6 +76,8 @@ void Environment::loadOperators()
 
 	ADD_FUNCTION(
 		"/",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_AT_LEAST("/", SIZE(), 1);
 
@@ -86,6 +97,8 @@ void Environment::loadOperators()
 	// (% 5 2) -> 1
 	ADD_FUNCTION(
 		"%",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("/", SIZE(), 2);
 

src/env/functions/other.cpp

@@ -5,9 +5,7 @@
  */
 
 #include <chrono>  // std::chrono::sytem_clock
-#include <cstddef> // size_t
 #include <cstdint> // int64_t
-#include <memory>  // std::static_pointer_cast
 
 #include "ast.h"
 #include "env/macro.h"
@@ -22,6 +20,8 @@ void Environment::loadOther()
 	// (throw x)
 	ADD_FUNCTION(
 		"throw",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("throw", SIZE(), 1);
 
@@ -35,6 +35,8 @@ void Environment::loadOther()
 	// (time-ms)
 	ADD_FUNCTION(
 		"time-ms",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("time-ms", SIZE(), 0);
 

src/env/functions/predicate.cpp

@@ -22,9 +22,9 @@ void Environment::loadPredicate()
 	}
 
 	// (nil? nil)
-	ADD_FUNCTION("nil?", IS_CONSTANT("nil?", Constant::Nil));
-	ADD_FUNCTION("true?", IS_CONSTANT("true?", Constant::True));
-	ADD_FUNCTION("false?", IS_CONSTANT("false?", Constant::False));
+	ADD_FUNCTION("nil?", "", "", IS_CONSTANT("nil?", Constant::Nil));
+	ADD_FUNCTION("true?", "", "", IS_CONSTANT("true?", Constant::True));
+	ADD_FUNCTION("false?", "", "", IS_CONSTANT("false?", Constant::False));
 
 	// -----------------------------------------
 
@@ -47,18 +47,20 @@ void Environment::loadPredicate()
 	}
 
 	// (symbol? 'foo)
-	ADD_FUNCTION("atom?", IS_TYPE(Atom));
-	ADD_FUNCTION("keyword?", IS_TYPE(Keyword));
-	ADD_FUNCTION("list?", IS_TYPE(List));
-	ADD_FUNCTION("map?", IS_TYPE(HashMap));
-	ADD_FUNCTION("number?", IS_TYPE(Number));
-	ADD_FUNCTION("sequential?", IS_TYPE(Collection));
-	ADD_FUNCTION("string?", IS_TYPE(String));
-	ADD_FUNCTION("symbol?", IS_TYPE(Symbol));
-	ADD_FUNCTION("vector?", IS_TYPE(Vector));
+	ADD_FUNCTION("atom?", "", "", IS_TYPE(Atom));
+	ADD_FUNCTION("keyword?", "", "", IS_TYPE(Keyword));
+	ADD_FUNCTION("list?", "", "", IS_TYPE(List));
+	ADD_FUNCTION("map?", "", "", IS_TYPE(HashMap));
+	ADD_FUNCTION("number?", "", "", IS_TYPE(Number));
+	ADD_FUNCTION("sequential?", "", "", IS_TYPE(Collection));
+	ADD_FUNCTION("string?", "", "", IS_TYPE(String));
+	ADD_FUNCTION("symbol?", "", "", IS_TYPE(Symbol));
+	ADD_FUNCTION("vector?", "", "", IS_TYPE(Vector));
 
 	ADD_FUNCTION(
 		"fn?",
+		"",
+		"",
 		{
 			bool result = true;
 
@@ -78,6 +80,8 @@ void Environment::loadPredicate()
 
 	ADD_FUNCTION(
 		"macro?",
+		"",
+		"",
 		{
 			bool result = true;
 
@@ -101,6 +105,8 @@ void Environment::loadPredicate()
 	// (contains? {"bar" 5} "foo") -> false
 	ADD_FUNCTION(
 		"contains?",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("contains?", SIZE(), 2);
 
@@ -117,6 +123,8 @@ void Environment::loadPredicate()
 	// (empty? [] [1 2 3] []) -> false
 	ADD_FUNCTION(
 		"empty?",
+		"",
+		"",
 		{
 			bool result = true;
 

src/env/functions/repl.cpp

@@ -19,6 +19,8 @@ void Environment::loadRepl()
 	// REPL reader
 	ADD_FUNCTION(
 		"read-string",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("read-string", SIZE(), 1);
 
@@ -31,6 +33,8 @@ void Environment::loadRepl()
 	// Read file contents
 	ADD_FUNCTION(
 		"slurp",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("slurp", SIZE(), 1);
 
@@ -45,6 +49,8 @@ void Environment::loadRepl()
 	// Prompt readline
 	ADD_FUNCTION(
 		"readline",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("readline", SIZE(), 1);
 
@@ -56,6 +62,8 @@ void Environment::loadRepl()
 	// REPL eval
 	ADD_FUNCTION(
 		"eval",
+		"",
+		"",
 		{
 			CHECK_ARG_COUNT_IS("eval", SIZE(), 1);
 

src/env/macro.h

@@ -8,9 +8,11 @@
 
 #include "env/environment.h"
 
-#define ADD_FUNCTION(symbol, lambda) \
+#define ADD_FUNCTION(name, signature, documentation, lambda) \
 	Environment::registerFunction(                           \
-		symbol,                      \
-		[](ValueVectorConstIt begin, ValueVectorConstIt end) -> blaze::ValuePtr lambda);
+		{ name,                                              \
+	      signature,                                         \
+	      documentation,                                     \
+	      [](ValueVectorConstIt begin, ValueVectorConstIt end) -> blaze::ValuePtr lambda });
 
 #define SIZE() std::distance(begin, end)

src/eval-special-form.cpp

@@ -4,17 +4,26 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <algorithm> // std::find_if, std::transform
+#include <cctype>    // std::toupper
 #include <iterator>  // std::distance, std::next, std::prev
 #include <list>
 #include <memory>
 #include <span>
 #include <string>
 
+#include "ruc/format/color.h"
+#include "ruc/format/format.h"
+#include "ruc/format/print.h"
+
 #include "ast.h"
 #include "env/environment.h"
 #include "error.h"
 #include "eval.h"
 #include "forward.h"
+#include "macro.h"
+#include "printer.h"
+#include "settings.h"
 #include "types.h"
 #include "util.h"
 
@@ -22,7 +31,7 @@ namespace blaze {
 
 static ValuePtr evalQuasiQuoteImpl(ValuePtr ast);
 
-// (def! x 2)
+EVAL_FUNCTION("def!", "symbol value", "Set SYMBOL to the value VALUE.");
 ValuePtr Eval::evalDef(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_IS("def!", nodes.size(), 2);
@@ -44,7 +53,13 @@ ValuePtr Eval::evalDef(const ValueVector& nodes, EnvironmentPtr env)
 	return env->set(symbol->symbol(), value);
 }
 
-// (defmacro! x (fn* (x) x))
+EVAL_FUNCTION("defmacro!", "symbol function",
+              R"(Define SYMBOL as a macro.
+
+When the macro is called, as in (NAME ARGS...),
+the FUNCTION (fn* ARGLIST BODY...) is applied to
+the list ARGS... as it appears in the expression,
+and the result should be a form to be evaluated instead of the original.)");
 ValuePtr Eval::evalDefMacro(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_IS("defmacro!", nodes.size(), 2);
@@ -67,7 +82,139 @@ ValuePtr Eval::evalDefMacro(const ValueVector& nodes, EnvironmentPtr env)
 	return env->set(symbol->symbol(), makePtr<Macro>(*lambda));
 }
 
-// (fn* (x) x)
+EVAL_FUNCTION("describe", "symbol", "Display the full documentation of SYMBOL.");
+ValuePtr Eval::evalDescribe(const ValueVector& nodes, EnvironmentPtr env)
+{
+	CHECK_ARG_COUNT_IS("describe", nodes.size(), 1);
+
+	// First argument needs to be a Symbol
+	VALUE_CAST(symbol, Symbol, nodes.front());
+	auto symbol_string = symbol->symbol();
+
+	std::string type;
+	std::string signature;
+	std::string documentation;
+	std::string value_string;
+
+	bool pretty_print = Settings::the().get("pretty-print") == "1";
+	auto bold = fg(ruc::format::TerminalColor::None) | ruc::format::Emphasis::Bold;
+
+	auto describe = [&]() {
+		print("{} is a {}.\n\n", symbol_string, type);
+
+		if (!signature.empty()) {
+			pretty_print ? print(bold, "Signature\n") : print("Signature\n");
+			print("({})\n", signature);
+		}
+
+		if (!documentation.empty()) {
+			pretty_print ? print(bold, "\nDocumentation\n") : print("\nDocumentation\n");
+			print("{}\n", documentation);
+		}
+
+		if (!value_string.empty()) {
+			pretty_print ? print(bold, "Value\n") : print("Value\n");
+			print("{}\n", value_string);
+		}
+	};
+
+	// Verify if symbol is a special form
+	auto special_form = std::find_if(
+		s_special_form_parts.begin(),
+		s_special_form_parts.end(),
+		[&symbol_string](const SpecialFormParts& special_form_parts) {
+			return special_form_parts.name == symbol_string;
+		});
+
+	// If symbol is not special form, lookup in the environment
+	ValuePtr value;
+	if (special_form == s_special_form_parts.end()) {
+		value = env->get(symbol_string);
+		if (!value) {
+			Error::the().add(format("'{}' not found", symbol_string));
+			return nullptr;
+		}
+	}
+
+	// Variable
+	if (special_form == s_special_form_parts.end() && !is<Callable>(value.get())) {
+		type = "variable";
+
+		Printer printer;
+		value_string = format("{}", printer.printNoErrorCheck(value, true));
+
+		describe();
+
+		return nullptr;
+	}
+
+	signature = pretty_print ? format(fg(ruc::format::TerminalColor::BrightBlue), "{}", symbol_string)
+	                         : symbol_string;
+
+	// Special form
+	if (special_form != s_special_form_parts.end()) {
+		type = "special form";
+
+		std::string signature_lower = std::string(special_form->signature);
+		std::transform(signature_lower.begin(), signature_lower.end(), signature_lower.begin(), ::toupper);
+		signature += !signature_lower.empty() ? " " : "";
+		signature += signature_lower;
+
+		documentation = special_form->documentation;
+
+		describe();
+
+		return nullptr;
+	}
+
+	// Function / lambda / macro
+	if (is<Function>(value.get())) {
+		type = "function";
+
+		auto function = std::static_pointer_cast<Function>(value);
+		signature += !function->signature().empty() ? " " : "";
+		signature += function->signature();
+
+		documentation = function->documentation();
+	}
+	else if (is<Lambda>(value.get()) || is<Macro>(value.get())) {
+		type = is<Lambda>(value.get()) ? "function" : "macro";
+
+		auto lambda = std::static_pointer_cast<Lambda>(value);
+		auto bindings = lambda->bindings();
+		std::string binding;
+		for (size_t i = 0; i < bindings.size(); ++i) {
+			binding = bindings[i];
+			std::transform(binding.begin(), binding.end(), binding.begin(), ::toupper);
+			signature += " " + binding;
+		}
+
+		auto body = lambda->body();
+		if (is<String>(body.get())) {
+			documentation = std::static_pointer_cast<String>(body)->data();
+		}
+		else if (is<List>(body.get())) {
+			VALUE_CAST(list, List, body);
+			if (list->size() > 1) {
+				auto second = list->nodesRead()[1];
+				if (is<String>(second.get())) {
+					documentation = std::static_pointer_cast<String>(second)->data();
+				}
+			}
+		}
+	}
+
+	describe();
+
+	return nullptr;
+}
+
+EVAL_FUNCTION("fn*", "args [docstring] body...", R"(Return an anonymous function.
+
+ARGS should take the form of an argument list or vector.
+DOCSTRING is an optional documentation string.
+ If present, it should describe how to call the function.
+BODY should be a list of Lisp expressions.)");
 ValuePtr Eval::evalFn(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_AT_LEAST("fn*", nodes.size(), 2);
@@ -102,6 +249,7 @@ ValuePtr Eval::evalFn(const ValueVector& nodes, EnvironmentPtr env)
 // -----------------------------------------
 
 // (quasiquoteexpand x)
+EVAL_FUNCTION("quasiquoteexpand", "arg", ""); // TODO
 ValuePtr Eval::evalQuasiQuoteExpand(const ValueVector& nodes)
 {
 	CHECK_ARG_COUNT_IS("quasiquoteexpand", nodes.size(), 1);
@@ -109,7 +257,7 @@ ValuePtr Eval::evalQuasiQuoteExpand(const ValueVector& nodes)
 	return evalQuasiQuoteImpl(nodes.front());
 }
 
-// (quote x)
+EVAL_FUNCTION("quote", "arg", "Return the ARG, without evaluating it. (quote x) yields x.");
 ValuePtr Eval::evalQuote(const ValueVector& nodes)
 {
 	CHECK_ARG_COUNT_IS("quote", nodes.size(), 1);
@@ -117,7 +265,13 @@ ValuePtr Eval::evalQuote(const ValueVector& nodes)
 	return nodes.front();
 }
 
-// (try* x ... (catch* y z))
+EVAL_FUNCTION("try*", "body... [catch]", R"(Eval BODY allowing exceptions to get caught.
+
+CATCH should take the form of (catch* binding handler).
+
+The BODY is evaluated, if it throws an exception, then form CATCH is
+handled by creating a new environment that binds the symbol BINDING
+to the value of the exception that was thrown. Finally, HANDLER is evaluated.)");
 ValuePtr Eval::evalTry(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_AT_LEAST("try*", nodes.size(), 1);
@@ -169,11 +323,11 @@ ValuePtr Eval::evalTry(const ValueVector& nodes, EnvironmentPtr env)
 
 	VALUE_CAST(catch_binding, Symbol, (*std::next(catch_nodes.begin())));
 
-	// Create new Environment that binds 'y' to the value of the exception
+	// Create new Environment that binds 'binding' to the value of the exception
 	auto catch_env = Environment::create(env);
 	catch_env->set(catch_binding->symbol(), error);
 
-	// Evaluate 'z' using the new Environment
+	// Evaluate 'handler' using the new Environment
 	m_ast = catch_nodes.back();
 	m_env = catch_env;
 	return evalImpl();
@@ -181,7 +335,10 @@ ValuePtr Eval::evalTry(const ValueVector& nodes, EnvironmentPtr env)
 
 // -----------------------------------------
 
-// (and 1 2 3)
+EVAL_FUNCTION("and", "args...", R"(Eval ARGS until one of them yields nil, then return nil.
+
+The remaining args are not evalled at all.
+If no arg yields nil, return the last arg's value.)");
 void Eval::evalAnd(const ValueVector& nodes, EnvironmentPtr env)
 {
 	ValuePtr result = makePtr<Constant>(Constant::True);
@@ -205,7 +362,7 @@ void Eval::evalAnd(const ValueVector& nodes, EnvironmentPtr env)
 	return; // TCO
 }
 
-// (do 1 2 3)
+EVAL_FUNCTION("do", "body...", "Eval BODY forms sequentially and return value of the last one.");
 void Eval::evalDo(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_AT_LEAST("do", nodes.size(), 1, void());
@@ -223,7 +380,11 @@ void Eval::evalDo(const ValueVector& nodes, EnvironmentPtr env)
 	return; // TCO
 }
 
-// (if x true false)
+EVAL_FUNCTION("if", "COND THEN [ELSE]", R"(If COND yields non-nil, do THEN, else do ELSE.
+
+Returns the value of THEN or the value of ELSE.
+Both THEN and ELSE must be one expression.
+If COND yields nil, and there is no ELSE, the value is nil.)");
 void Eval::evalIf(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_BETWEEN("if", nodes.size(), 2, 3, void());
@@ -247,7 +408,12 @@ void Eval::evalIf(const ValueVector& nodes, EnvironmentPtr env)
 	return; // TCO
 }
 
-// (let* (x 1) x)
+EVAL_FUNCTION("let*", "varlist body", R"(Bind variables accoring to VARLIST then eval BODY.
+
+The value of the BODY form is returned.
+VARLIST is a list or vector with an even amount of elements,
+where each odd number is a symbol gets bind the even element.
+All even elements are evalled before any symbols are bound.)");
 void Eval::evalLet(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_IS("let*", nodes.size(), 2, void());
@@ -307,6 +473,7 @@ static bool isMacroCall(ValuePtr ast, EnvironmentPtr env)
 	return true;
 }
 
+EVAL_FUNCTION("macroexpand-1", "expression", "Macroexpand EXPRESSION and pretty-print its value.");
 void Eval::evalMacroExpand1(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_IS("macroexpand-1", nodes.size(), 1, void());
@@ -329,7 +496,10 @@ void Eval::evalMacroExpand1(const ValueVector& nodes, EnvironmentPtr env)
 
 // -----------------------------------------
 
-// (or 1 2 3)
+EVAL_FUNCTION("or", "args...", R"(Eval ARGS until one of them yields non-nil, then return that value.
+
+The remaining args are not evalled at all.
+If all args return nil, return nil.)");
 void Eval::evalOr(const ValueVector& nodes, EnvironmentPtr env)
 {
 	ValuePtr result;
@@ -442,6 +612,7 @@ static ValuePtr evalQuasiQuoteImpl(ValuePtr ast)
 }
 
 // (quasiquote x)
+EVAL_FUNCTION("quasiquote", "arg", R"()"); // TODO
 void Eval::evalQuasiQuote(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_IS("quasiquote", nodes.size(), 1, void());
@@ -456,6 +627,12 @@ void Eval::evalQuasiQuote(const ValueVector& nodes, EnvironmentPtr env)
 // -----------------------------------------
 
 // (while true body...)
+EVAL_FUNCTION("while", "test body...", R"(If TEST yields non-nil, eval BODY... and repeat
+
+The order of execution is thus TEST, BODY, TEST, BODY and so on
+until TEST returns nil.
+
+The value of a while form is always nil.)");
 void Eval::evalWhile(const ValueVector& nodes, EnvironmentPtr env)
 {
 	CHECK_ARG_COUNT_AT_LEAST("while", nodes.size(), 2, void());

src/eval.cpp

@@ -20,6 +20,8 @@
 
 namespace blaze {
 
+std::vector<SpecialFormParts> Eval::s_special_form_parts;
+
 Eval::Eval(ValuePtr ast, EnvironmentPtr env)
 	: m_ast(ast)
 	, m_env(env)
@@ -29,6 +31,11 @@ Eval::Eval(ValuePtr ast, EnvironmentPtr env)
 
 // -----------------------------------------
 
+void Eval::registerSpecialForm(SpecialFormParts special_form_parts)
+{
+	s_special_form_parts.push_back(special_form_parts);
+}
+
 void Eval::eval()
 {
 	m_ast = evalImpl();
@@ -80,6 +87,9 @@ ValuePtr Eval::evalImpl()
 			if (symbol == "defmacro!") {
 				return evalDefMacro(nodes, env);
 			}
+			if (symbol == "describe") {
+				return evalDescribe(nodes, env);
+			}
 			if (symbol == "fn*") {
 				return evalFn(nodes, env);
 			}

src/eval.h

@@ -6,21 +6,27 @@
 
 #pragma once
 
-#include <list>
-#include <stack>
+#include <vector>
 
 #include "env/environment.h"
 #include "forward.h"
 
 namespace blaze {
 
-class List;
+// All of these combined become a Function in the Environment
+struct SpecialFormParts {
+	std::string_view name;
+	std::string_view signature;
+	std::string_view documentation;
+};
 
 class Eval {
 public:
 	Eval(ValuePtr ast, EnvironmentPtr env);
 	virtual ~Eval() = default;
 
+	static void registerSpecialForm(SpecialFormParts special_form_parts);
+
 	void eval();
 
 	ValuePtr ast() const { return m_ast; }
@@ -33,6 +39,7 @@ private:
 
 	ValuePtr evalDef(const ValueVector& nodes, EnvironmentPtr env);
 	ValuePtr evalDefMacro(const ValueVector& nodes, EnvironmentPtr env);
+	ValuePtr evalDescribe(const ValueVector& nodes, EnvironmentPtr env);
 	ValuePtr evalFn(const ValueVector& nodes, EnvironmentPtr env);
 	ValuePtr evalQuasiQuoteExpand(const ValueVector& nodes);
 	ValuePtr evalQuote(const ValueVector& nodes);
@@ -52,6 +59,8 @@ private:
 	ValuePtr m_ast;
 	EnvironmentPtr m_env;
 	EnvironmentPtr m_outer_env;
+
+	static std::vector<SpecialFormParts> s_special_form_parts;
 };
 
 } // namespace blaze

src/macro.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2023 Riyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "eval.h"
+
+#define CONCAT(a, b) CONCAT_IMPL(a, b)
+#define CONCAT_IMPL(a, b) a##b
+
+#define EVAL_FUNCTION_IMPL(name, signature, documentation, struct_name)    \
+	struct struct_name {                                                   \
+		struct_name()                                                      \
+		{                                                                  \
+			Eval::registerSpecialForm({ name, signature, documentation }); \
+		}                                                                  \
+	};                                                                     \
+	static struct struct_name struct_name; // NOLINT(clang-diagnostic-unused-function)
+
+#define EVAL_FUNCTION(name, signature, documentation) \
+	EVAL_FUNCTION_IMPL(name, signature, documentation, CONCAT(__EVAL_STRUCT_, __COUNTER__))