diff --git a/include/asm/charmap.hpp b/include/asm/charmap.hpp
index b92e36a2..aa416236 100644
--- a/include/asm/charmap.hpp
+++ b/include/asm/charmap.hpp
@@ -4,17 +4,18 @@
 #define RGBDS_ASM_CHARMAP_H
 
 #include <stdint.h>
+#include <string>
 #include <vector>
 
 #define DEFAULT_CHARMAP_NAME "main"
 
-void charmap_New(char const *name, char const *baseName);
-void charmap_Set(char const *name);
+void charmap_New(std::string const &name, std::string const *baseName);
+void charmap_Set(std::string const &name);
 void charmap_Push();
 void charmap_Pop();
-void charmap_Add(char const *mapping, uint8_t value);
-bool charmap_HasChar(char const *input);
-void charmap_Convert(char const *input, std::vector<uint8_t> &output);
+void charmap_Add(std::string const &mapping, uint8_t value);
+bool charmap_HasChar(std::string const &input);
+void charmap_Convert(std::string const &input, std::vector<uint8_t> &output);
 size_t charmap_ConvertNext(char const *&input, std::vector<uint8_t> *output);
 
 #endif // RGBDS_ASM_CHARMAP_H
diff --git a/src/asm/charmap.cpp b/src/asm/charmap.cpp
index ec2d08d4..649f79fd 100644
--- a/src/asm/charmap.cpp
+++ b/src/asm/charmap.cpp
@@ -7,7 +7,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <string>
 #include <unordered_map>
 
 #include "util.hpp"
@@ -36,20 +35,20 @@ static std::unordered_map<std::string, Charmap> charmaps;
 static Charmap *currentCharmap;
 std::stack<Charmap *> charmapStack;
 
-void charmap_New(char const *name, char const *baseName) {
+void charmap_New(std::string const &name, std::string const *baseName) {
 	Charmap *base = nullptr;
 
 	if (baseName != nullptr) {
-		auto search = charmaps.find(baseName);
+		auto search = charmaps.find(*baseName);
 
 		if (search == charmaps.end())
-			error("Base charmap '%s' doesn't exist\n", baseName);
+			error("Base charmap '%s' doesn't exist\n", baseName->c_str());
 		else
 			base = &search->second;
 	}
 
 	if (charmaps.find(name) != charmaps.end()) {
-		error("Charmap '%s' already exists\n", name);
+		error("Charmap '%s' already exists\n", name.c_str());
 		return;
 	}
 
@@ -65,11 +64,11 @@ void charmap_New(char const *name, char const *baseName) {
 	currentCharmap = &charmap;
 }
 
-void charmap_Set(char const *name) {
+void charmap_Set(std::string const &name) {
 	auto search = charmaps.find(name);
 
 	if (search == charmaps.end())
-		error("Charmap '%s' doesn't exist\n", name);
+		error("Charmap '%s' doesn't exist\n", name.c_str());
 	else
 		currentCharmap = &search->second;
 }
@@ -88,12 +87,12 @@ void charmap_Pop() {
 	charmapStack.pop();
 }
 
-void charmap_Add(char const *mapping, uint8_t value) {
+void charmap_Add(std::string const &mapping, uint8_t value) {
 	Charmap &charmap = *currentCharmap;
 	size_t nodeIdx = 0;
 
-	for (; *mapping; mapping++) {
-		size_t &nextIdxRef = charmap.nodes[nodeIdx].next[(uint8_t)*mapping - 1];
+	for (char c : mapping) {
+		size_t &nextIdxRef = charmap.nodes[nodeIdx].next[(uint8_t)c - 1];
 		size_t nextIdx = nextIdxRef;
 
 		if (!nextIdx) {
@@ -117,12 +116,12 @@ void charmap_Add(char const *mapping, uint8_t value) {
 	node.value = value;
 }
 
-bool charmap_HasChar(char const *input) {
+bool charmap_HasChar(std::string const &input) {
 	Charmap const &charmap = *currentCharmap;
 	size_t nodeIdx = 0;
 
-	for (; *input; input++) {
-		nodeIdx = charmap.nodes[nodeIdx].next[(uint8_t)*input - 1];
+	for (char c : input) {
+		nodeIdx = charmap.nodes[nodeIdx].next[(uint8_t)c - 1];
 
 		if (!nodeIdx)
 			return false;
@@ -131,8 +130,9 @@ bool charmap_HasChar(char const *input) {
 	return charmap.nodes[nodeIdx].isTerminal;
 }
 
-void charmap_Convert(char const *input, std::vector<uint8_t> &output) {
-	while (charmap_ConvertNext(input, &output))
+void charmap_Convert(std::string const &input, std::vector<uint8_t> &output) {
+	char const *ptr = input.c_str();
+	while (charmap_ConvertNext(ptr, &output))
 		;
 }
 
diff --git a/src/asm/parser.y b/src/asm/parser.y
index 1da30043..53dc634c 100644
--- a/src/asm/parser.y
+++ b/src/asm/parser.y
@@ -1141,22 +1141,22 @@ incbin:
 
 charmap:
 	POP_CHARMAP string COMMA const_8bit {
-		charmap_Add($2.c_str(), (uint8_t)$4);
+		charmap_Add($2, (uint8_t)$4);
 	}
 ;
 
 newcharmap:
 	POP_NEWCHARMAP ID {
-		charmap_New($2.c_str(), nullptr);
+		charmap_New($2, nullptr);
 	}
 	| POP_NEWCHARMAP ID COMMA ID {
-		charmap_New($2.c_str(), $4.c_str());
+		charmap_New($2, &$4);
 	}
 ;
 
 setcharmap:
 	POP_SETCHARMAP ID {
-		charmap_Set($2.c_str());
+		charmap_Set($2);
 	}
 ;
 
@@ -1224,7 +1224,7 @@ constlist_8bit_entry:
 	| string {
 		std::vector<uint8_t> output;
 
-		charmap_Convert($1.c_str(), output);
+		charmap_Convert($1, output);
 		sect_AbsByteGroup(output.data(), output.size());
 	}
 ;
@@ -1241,7 +1241,7 @@ constlist_16bit_entry:
 	| string {
 		std::vector<uint8_t> output;
 
-		charmap_Convert($1.c_str(), output);
+		charmap_Convert($1, output);
 		sect_AbsWordGroup(output.data(), output.size());
 	}
 ;
@@ -1258,7 +1258,7 @@ constlist_32bit_entry:
 	| string {
 		std::vector<uint8_t> output;
 
-		charmap_Convert($1.c_str(), output);
+		charmap_Convert($1, output);
 		sect_AbsLongGroup(output.data(), output.size());
 	}
 ;
@@ -1309,7 +1309,7 @@ relocexpr:
 	| string {
 		std::vector<uint8_t> output;
 
-		charmap_Convert($1.c_str(), output);
+		charmap_Convert($1, output);
 		rpn_Number($$, str2int2(output));
 	}
 ;
@@ -1492,7 +1492,7 @@ relocexpr_no_str:
 		rpn_Number($$, charlenUTF8($3));
 	}
 	| OP_INCHARMAP LPAREN string RPAREN {
-		rpn_Number($$, charmap_HasChar($3.c_str()));
+		rpn_Number($$, charmap_HasChar($3));
 	}
 	| LPAREN relocexpr RPAREN {
 		$$ = std::move($2);