add ast_print

ast.h

@@ -1,6 +1,6 @@
 #pragma once
 
-struct token;
+#include "lexer.h"
 
 struct expression {
   struct token constant;
@@ -20,7 +20,7 @@ struct statement_return {
 struct statement_if_else {
   struct expression * expression;
   struct statement * statement_if;
-  struct statement * statement_else;
+  struct statement * statement_else; // might be nullptr
 };
 
 struct statement {
@@ -32,7 +32,7 @@ struct statement {
 };
 
 struct function_definition {
-  struct token * name;
+  struct token name;
   struct statement * statements;
 };
 

ast_print.c

@@ -0,0 +1,106 @@
+#include "assert.h"
+#include "printf.h"
+#include "ast_print.h"
+
+static void print_indent(int indent)
+{
+  for (int i = 0; i < indent; i++) {
+    print_char(' ');
+    print_char(' ');
+  }
+}
+
+#define printi(indent, ...)                     \
+  do {                                          \
+    print_indent(indent);                       \
+    _printf(__VA_ARGS__);                       \
+  } while (0);
+
+const char * statement_type_str(enum statement_type type)
+{
+  static const char * map[] = {
+    [STATEMENT_RETURN] = "STATEMENT_RETURN",
+    [STATEMENT_IF_ELSE] = "STATEMENT_IF_ELSE",
+  };
+  assert(((int)type) < ((sizeof (map)) / (sizeof (map[0]))));
+  return map[(int)type];
+}
+
+const char * token_type_str(enum token_type type) {
+  static const char * map[] = {
+    [TOKEN_INVALID] = "TOKEN_INVALID",
+    [TOKEN_EOF] = "TOKEN_EOF",
+    [TOKEN_IDENTIFIER] = "TOKEN_IDENTIFIER",
+    [TOKEN_CONSTANT] = "TOKEN_CONSTANT",
+    [TOKEN_INT] = "TOKEN_INT",
+    [TOKEN_VOID] = "TOKEN_VOID",
+    [TOKEN_RETURN] = "TOKEN_RETURN",
+    [TOKEN_LPAREN] = "TOKEN_LPAREN",
+    [TOKEN_RPAREN] = "TOKEN_RPAREN",
+    [TOKEN_LBRACE] = "TOKEN_LBRACE",
+    [TOKEN_RBRACE] = "TOKEN_RBRACE",
+    [TOKEN_SEMICOLON] = "TOKEN_SEMICOLON",
+  };
+  assert(((int)type) < ((sizeof (map)) / (sizeof (map[0]))));
+  return map[(int)type];
+}
+
+void print_token(int indent, struct token token)
+{
+  printi(indent, "type=%s str=", token_type_str(token.type));
+  const uint8_t * bufi = token.start;
+  while (bufi < token.end) {
+    print_char((char)*bufi++);
+  }
+  print_char('\n');
+}
+
+void print_expression(int indent, struct expression * expression)
+{
+  printi(indent, "token=(\n");
+  print_token(indent + 1, expression->constant);
+  printi(indent, ")\n");
+}
+
+void print_return(int indent, struct statement_return * statement_return)
+{
+  printi(indent, "expression=(\n");
+  print_expression(indent + 1, statement_return->expression);
+  printi(indent, ")\n");
+}
+
+void print_if_else(int indent, struct statement_if_else * statement_if_else)
+{
+  printi(indent, "expression=(\n");
+  print_expression(indent + 1, statement_if_else->expression);
+  printi(indent, ")\n");
+  printi(indent, "statement_if=(\n");
+  print_statement(indent + 1, statement_if_else->statement_if);
+  printi(indent, ")\n");
+  printi(indent, "statement_else=(\n");
+  if (statement_if_else->statement_else == nullptr) {
+    printi(indent + 1, "nullptr\n");
+  } else {
+    print_statement(indent + 1, statement_if_else->statement_else);
+  }
+  printi(indent, ")\n");
+}
+
+void print_statement(int indent, struct statement * statement)
+{
+  printi(indent, "statement type=%s (\n", statement_type_str(statement->type));
+  switch (statement->type) {
+  case STATEMENT_RETURN:  print_return(indent + 1, statement->statement_return); break;
+  case STATEMENT_IF_ELSE: print_if_else(indent + 1, statement->statement_if_else); break;
+  default:
+    assert(false);
+    break;
+  }
+  printi(indent, ")\n");
+}
+
+void print_function_definition(int indent, struct statement * statement)
+{
+  printi(indent, "function_definition name=");
+  print_token(statement->name);
+}

ast_print.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "ast.h"
+
+const char * statement_type_str(enum statement_type type);
+const char * token_type_str(enum token_type type);
+
+void print_token(int indent, struct token token);
+void print_expression(int indent, struct expression * expression);
+void print_return(int indent, struct statement_return * statement_return);
+void print_if_else(int indent, struct statement_if_else * statement_if_else);
+void print_statement(int indent, struct statement * statement);

compiler.mk

@@ -5,4 +5,5 @@ OBJ = \
 	printf.o \
 	string_parse.o \
 	string_unparse.o \
+	ast_print.o \
 	main_hosted.o

lexer.c

@@ -80,12 +80,14 @@ static inline enum token_type find_keyword(const uint8_t * buf, int start, int e
 struct token lexer_next_token(struct lexer_state * state)
 {
   struct token token;
+  int token_start;
+  int token_end;
 
   while (state->offset < state->size && is_whitespace(state->buf[state->offset])) {
     state->offset += 1;
   }
 
-  token.start = state->offset;
+  token_start = state->offset;
 
   uint8_t c = state->buf[state->offset++];
 
@@ -108,7 +110,7 @@ struct token lexer_next_token(struct lexer_state * state)
           break;
         state->offset += 1;
       }
-      token.type = find_keyword(state->buf, token.start, state->offset);
+      token.type = find_keyword(state->buf, token_start, state->offset);
     } else if (is_decimal_digit(c)) {
       while (state->offset < state->size) {
         uint8_t c = state->buf[state->offset];
@@ -128,10 +130,13 @@ struct token lexer_next_token(struct lexer_state * state)
     break;
   }
 
-  token.end = state->offset;
+  token_end = state->offset;
 
-  if (token.start >= state->size)
+  if (token_start >= state->size)
     token.type = TOKEN_EOF;
 
+  token.start = &state->buf[token_start];
+  token.end = &state->buf[token_end];
+
   return token;
 }

lexer.h

@@ -21,8 +21,8 @@ enum token_type {
 
 struct token {
   enum token_type type;
-  int start;
-  int end;
+  const uint8_t * start;
+  const uint8_t * end;
   int value;
 };
 

main_hosted.c

@@ -4,6 +4,7 @@
 #include <stdlib.h>
 
 #include "lexer.h"
+#include "ast_print.h"
 
 int read_file(const char * filename, uint8_t ** buf)
 {
@@ -50,21 +51,6 @@ int read_file(const char * filename, uint8_t ** buf)
   return size;
 }
 
-const char * token_str[] = {
-  [TOKEN_INVALID] = "TOKEN_INVALID",
-  [TOKEN_EOF] = "TOKEN_EOF",
-  [TOKEN_IDENTIFIER] = "TOKEN_IDENTIFIER",
-  [TOKEN_CONSTANT] = "TOKEN_CONSTANT",
-  [TOKEN_INT] = "TOKEN_INT",
-  [TOKEN_VOID] = "TOKEN_VOID",
-  [TOKEN_RETURN] = "TOKEN_RETURN",
-  [TOKEN_LPAREN] = "TOKEN_LPAREN",
-  [TOKEN_RPAREN] = "TOKEN_RPAREN",
-  [TOKEN_LBRACE] = "TOKEN_LBRACE",
-  [TOKEN_RBRACE] = "TOKEN_RBRACE",
-  [TOKEN_SEMICOLON] = "TOKEN_SEMICOLON",
-};
-
 int main(int argc, char * argv[])
 {
   if (argc != 3) {
@@ -89,7 +75,7 @@ int main(int argc, char * argv[])
 
   while (true) {
     struct token token = lexer_next_token(&lexer_state);
-    printf("%s\n", token_str[token.type]);
+    printf("%s\n", token_type_str(token.type));
     if (token.type == TOKEN_INVALID)
       return EXIT_FAILURE;
     if (token.type == TOKEN_EOF)