diff --git a/src/include/lexer.h b/src/include/lexer.h
index b52aff3..abfc94f 100644
--- a/src/include/lexer.h
+++ b/src/include/lexer.h
@@ -38,6 +38,7 @@ typedef struct {
 Lexer* lexer_init(char* src);
 
 // Destroy a lexer.
+// Does not destroy `lexer->src`!
 void lexer_destroy(Lexer* lexer);
 
 // Convert text to tokens.
diff --git a/src/include/parser.h b/src/include/parser.h
index 2ad30fd..026fd31 100644
--- a/src/include/parser.h
+++ b/src/include/parser.h
@@ -17,8 +17,9 @@ typedef struct {
 Parser* parser_init(size_t tokenc, Token** tokenv);
 void parser_destroy(Parser* parser);
 
-// Increment parser->ctoken.
+// Increment `parser->ctoken`.
 void parser_inc(Parser* parser);
+
 // Step forward 1 token and add to stacks.
 void parser_step(Parser* parser);
 
diff --git a/src/include/stack.h b/src/include/stack.h
index d0776c0..4962368 100644
--- a/src/include/stack.h
+++ b/src/include/stack.h
@@ -6,15 +6,18 @@
 #define STACK_MAX 64
 
 typedef struct {
-    size_t i;
-    void* val[STACK_MAX];
+    size_t i;               // Current index in the stack.
+    void* val[STACK_MAX];   // The stack itself.
 } Stack;
 
 Stack* stack_init();
-// stack->i must be 0.
+// Destroy a stack.
+// Note that `stack->i` must be `0`.
 void stack_destroy(Stack* stack);
 
+// Push a value to the stack.
 void stack_push(Stack* stack, void* val);
+// Pop a value from the stack.
 void* stack_pop(Stack* stack);
 
 #endif
diff --git a/src/lexer.c b/src/lexer.c
index 52f7add..680731a 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -24,8 +24,7 @@ Lexer* lexer_init(char* src) {
 }
 
 void lexer_destroy(Lexer* lexer) {
-    free(lexer->src);
-
+    // Does not free lexer->src.
     for (int i = 0; i < lexer->ntokens; i++) token_destroy(lexer->tokens[i]);
 }
 
diff --git a/src/main.c b/src/main.c
index c7ad97f..ad2bd23 100644
--- a/src/main.c
+++ b/src/main.c
@@ -20,6 +20,9 @@ int main(int argc, char** argv) {
             Lexer* lexer = lexer_init(cline->buf);
             lexer_lex(lexer);
             lexer_print(lexer);
+            lexer_destroy(lexer);
         }
+
+        dstr_destroy(cline);
     }
 }