Env: Add string/number conversion functions

src/env/functions/convert.cpp

@@ -4,6 +4,9 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <charconv>     // std::from_chars, std::to_chars
+#include <system_error> // std::errc
+
 #include "ast.h"
 #include "env/macro.h"
 #include "util.h"
@@ -12,6 +15,79 @@ namespace blaze {
 
 void Environment::loadConvert()
 {
+	// (number-to-string 123) -> "123"
+	ADD_FUNCTION(
+		"number-to-string",
+		{
+			CHECK_ARG_COUNT_IS("number-to-string", SIZE(), 1);
+
+			VALUE_CAST(number, Number, (*begin));
+
+			char result[32];
+			auto conversion = std::to_chars(result,
+		                                    result + sizeof(result),
+		                                    number->number());
+			if (conversion.ec != std::errc()) {
+				return makePtr<Constant>(Constant::Nil);
+			}
+
+			return makePtr<String>(std::string(result, conversion.ptr - result));
+		});
+
+	// (string-to-char "123") -> 49
+	ADD_FUNCTION(
+		"string-to-char",
+		{
+			CHECK_ARG_COUNT_IS("string-to-char", SIZE(), 1);
+
+			VALUE_CAST(string_value, String, (*begin));
+			std::string data = string_value->data();
+
+			return makePtr<Number>(data.c_str()[0]);
+		});
+
+	// (string-to-number "123") -> 123
+	ADD_FUNCTION(
+		"string-to-number",
+		{
+			CHECK_ARG_COUNT_IS("string-to-number", SIZE(), 1);
+
+			VALUE_CAST(string_value, String, (*begin));
+			std::string data = string_value->data();
+
+			int64_t result;
+			auto conversion = std::from_chars(data.c_str(),
+		                                      data.c_str() + data.size(),
+		                                      result);
+			if (conversion.ec != std::errc()) {
+				return makePtr<Constant>(Constant::Nil);
+			}
+
+			return makePtr<Number>(result);
+		});
+
+#define STRING_TO_COLLECTION(name, type)                    \
+	{                                                       \
+		CHECK_ARG_COUNT_IS(name, SIZE(), 1);                \
+                                                            \
+		VALUE_CAST(string_value, String, (*begin));         \
+		std::string data = string_value->data();            \
+                                                            \
+		ValueVector nodes(data.size());                     \
+		for (size_t i = 0; i < data.size(); ++i) {          \
+			nodes.at(i) = makePtr<Number>(data.c_str()[i]); \
+		}                                                   \
+                                                            \
+		return makePtr<type>(nodes);                        \
+	}
+
+	// (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));
+
+	// -------------------------------------
+
 	// (symbol "foo")  -> foo
 	ADD_FUNCTION(
 		"symbol",
@@ -22,9 +98,9 @@ void Environment::loadConvert()
 				return *begin;
 			}
 
-			VALUE_CAST(stringValue, String, (*begin));
+			VALUE_CAST(string_value, String, (*begin));
 
-			return makePtr<Symbol>(stringValue->data());
+			return makePtr<Symbol>(string_value->data());
 		});
 
 	// (keyword "foo") -> :foo
@@ -32,20 +108,20 @@ void Environment::loadConvert()
 	ADD_FUNCTION(
 		"keyword",
 		{
-			CHECK_ARG_COUNT_IS("symbol", SIZE(), 1);
+			CHECK_ARG_COUNT_IS("keyword", SIZE(), 1);
 
 			if (is<Keyword>(begin->get())) {
 				return *begin;
 			}
 			else if (is<Number>(begin->get())) {
-				VALUE_CAST(numberValue, Number, (*begin));
+				VALUE_CAST(number_value, Number, (*begin));
 
-				return makePtr<Keyword>(numberValue->number());
+				return makePtr<Keyword>(number_value->number());
 			}
 
-			VALUE_CAST(stringValue, String, (*begin));
+			VALUE_CAST(string_value, String, (*begin));
 
-			return makePtr<Keyword>(stringValue->data());
+			return makePtr<Keyword>(string_value->data());
 		});
 }