diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6142305
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.o
+*.d
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..16d8666
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,43 @@
+%.csv: %.ods
+	libreoffice --headless --convert-to csv:"Text - txt - csv (StarCalc)":44,34,76,,,,true --outdir $(dir $@) $<
+
+include compiler.mk
+
+MAKEFILE_PATH := $(patsubst %/,%,$(dir $(abspath $(firstword $(MAKEFILE_LIST)))))
+CC ?= gcc
+ARCH = -m32
+CFLAGS += -Wall -Werror -Wfatal-errors -Wno-error=unused-variable -fstack-protector -std=c2x -g
+CFLAGS += -I$(MAKEFILE_PATH)/
+CFLAGS += -I$(MAKEFILE_PATH)/c
+CFLAGS += -DDEBUG
+#CFLAGS += -DDEBUG_PRINT
+LDFLAGS = -lm
+OPT ?= -O0
+DEPFLAGS = -MMD -MP
+
+%.o: %.c
+	$(CC) $(ARCH) $(CFLAGS) $(OPT) $(DEPFLAGS) -MF ${<}.d -c $< -o $@
+
+print_class: $(OBJ) $(PRINT_CLASS_OBJ)
+	$(CC) $(ARCH) $(LDFLAGS) $^ -o $@
+
+main: $(OBJ) $(MAIN_HOSTED_OBJ)
+	$(CC) $(ARCH) $(LDFLAGS) $^ -o $@
+
+clean:
+	rm -f main print_class *.elf *.bin
+	find -P \
+		-regextype posix-egrep \
+		-regex '.*\.(o|d|gch)$$' \
+		-exec rm {} \;
+
+.SUFFIXES:
+.INTERMEDIATE:
+.SECONDARY:
+.PHONY: all clean phony
+
+%: RCS/%,v
+%: RCS/%
+%: %,v
+%: s.%
+%: SCCS/s.%
diff --git a/assert_hosted.h b/assert_hosted.h
index 09dc5c0..599d08e 100644
--- a/assert_hosted.h
+++ b/assert_hosted.h
@@ -13,4 +13,4 @@ extern void __assert_fail (const char *__assertion, const char *__file,
   })
 
 #define fail(expr) \
-  (__assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION);)
+  (__assert_fail (#expr, __FILE__, __LINE__, __ASSERT_FUNCTION))
diff --git a/ast.h b/ast.h
index 982c95d..e0150e2 100644
--- a/ast.h
+++ b/ast.h
@@ -3,12 +3,11 @@
 struct token;
 
 struct expression {
-  struct token * constant;
+  struct token constant;
 };
 
 enum statement_type {
   STATEMENT_RETURN,
-  STATEMENT_IF,
   STATEMENT_IF_ELSE,
 };
 
@@ -18,21 +17,16 @@ struct statement_return {
   struct expression * expression;
 };
 
-struct statement_if {
-  struct expression * expression;
-  struct statement * statement;
-};
-
 struct statement_if_else {
   struct expression * expression;
-  struct statement * statement;
+  struct statement * statement_if;
+  struct statement * statement_else;
 };
 
 struct statement {
   enum statement_type type;
   union {
     struct statement_return * statement_return;
-    struct statement_if * statement_if;
     struct statement_if_else * statement_if_else;
   };
 };
diff --git a/compiler.mk b/compiler.mk
new file mode 100644
index 0000000..65cb20d
--- /dev/null
+++ b/compiler.mk
@@ -0,0 +1,8 @@
+OBJ = \
+	lexer.o \
+	parser.o \
+	malloc.o \
+	printf.o \
+	string_parse.o \
+	string_unparse.o \
+	main_hosted.o
diff --git a/lexer.c b/lexer.c
index 2fe7774..3251349 100644
--- a/lexer.c
+++ b/lexer.c
@@ -40,6 +40,16 @@ static const struct keyword_desc keywords[] = {
     .length = 6,
     .token_type = TOKEN_RETURN,
   },
+  {
+    .buf = (const uint8_t *)"if",
+    .length = 2,
+    .token_type = TOKEN_RETURN,
+  },
+  {
+    .buf = (const uint8_t *)"else",
+    .length = 4,
+    .token_type = TOKEN_RETURN,
+  },
 };
 
 static inline bool keyword_equal(const uint8_t * buf, int start, int end, const struct keyword_desc * keyword)
diff --git a/lexer.h b/lexer.h
index d7cd6b3..62b5f94 100644
--- a/lexer.h
+++ b/lexer.h
@@ -10,6 +10,8 @@ enum token_type {
   TOKEN_INT,
   TOKEN_VOID,
   TOKEN_RETURN,
+  TOKEN_IF,
+  TOKEN_ELSE,
   TOKEN_LPAREN,
   TOKEN_RPAREN,
   TOKEN_LBRACE,
diff --git a/malloc.h b/malloc.h
new file mode 100644
index 0000000..dca962f
--- /dev/null
+++ b/malloc.h
@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stdint.h>
+
+#define malloct(t) (malloc_class_arena((sizeof (t))))
+
+void * malloc_class_arena(uint32_t size);
diff --git a/minmax.h b/minmax.h
new file mode 100644
index 0000000..df4c506
--- /dev/null
+++ b/minmax.h
@@ -0,0 +1,4 @@
+#pragma once
+
+#define min(a, b) ( (a < b) ? a : b )
+#define max(a, b) ( (a > b) ? a : b )
diff --git a/parser.c b/parser.c
index 2de949d..72d528c 100644
--- a/parser.c
+++ b/parser.c
@@ -1,19 +1,14 @@
 #include "parser.h"
-#include "lexer.h"
 #include "assert.h"
-
-struct token_reader {
-  bool have_token;
-  struct token token;
-  struct lexer_state lexer_state;
-};
+#include "printf.h"
+#include "malloc.h"
 
 struct token peek(struct token_reader * reader)
 {
   if (reader->have_token) {
     return reader->token;
   } else {
-    reader->token = lexer_next_token(reader->lexer_state);
+    reader->token = lexer_next_token(&reader->lexer_state);
     reader->have_token = true;
     return reader->token;
   }
@@ -23,13 +18,73 @@ struct token consume(struct token_reader * reader)
 {
   struct token token = peek(reader);
   reader->have_token = false;
+  return token;
 }
 
-void expect_type(struct token_reader * reader, enum token_type token_type)
+bool match_type(struct token_reader * reader, enum token_type token_type)
 {
-  struct token token = consume(reader);
-  if (!(token->type == token_type)) {
-    printf("token->type=%d token_type=%d\n", token->type, token_type);
-    fail(token->type == token_type);
+  struct token token = peek(reader);
+  if (token.type == token_type) {
+    consume(reader);
+    return true;
+  } else {
+    return false;
   }
 }
+
+struct token expect_type(struct token_reader * reader, enum token_type token_type)
+{
+  struct token token = consume(reader);
+  if (!(token.type == token_type)) {
+    printf("token.type=%d token_type=%d\n", token.type, token_type);
+    fail(token.type == token_type);
+  }
+  return token;
+}
+
+struct expression * parse_expression(struct token_reader * reader)
+{
+  struct expression * expr = malloct(struct expression);
+  struct token token = expect_type(reader, TOKEN_CONSTANT);
+  expr->constant = token;
+  return expr;
+}
+
+struct statement_return * parse_statement_return(struct token_reader * reader)
+{
+  struct expression * expr = parse_expression(reader);
+  struct statement_return * stmt = malloct(struct statement_return);
+  stmt->expression = expr;
+  return stmt;
+}
+
+struct statement_if_else * parse_statement_if_else(struct token_reader * reader)
+{
+  struct statement_if_else * stmt = malloct(struct statement_if_else);
+  expect_type(reader, TOKEN_LPAREN);
+  struct expression * expr = parse_expression(reader);
+  expect_type(reader, TOKEN_RPAREN);
+  struct statement * statement_if = parse_statement(reader);
+  struct statement * statement_else = match_type(reader, TOKEN_ELSE) ? parse_statement(reader) : nullptr;
+  stmt->expression = expr;
+  stmt->statement_if = statement_if;
+  stmt->statement_else = statement_else;
+  return stmt;
+}
+
+struct statement * parse_statement(struct token_reader * reader)
+{
+  struct statement * stmt = malloct(struct statement);
+  if (match_type(reader, TOKEN_IF)) {
+    stmt->type = STATEMENT_IF_ELSE;
+    stmt->statement_if_else = parse_statement_if_else(reader);
+  } else if (match_type(reader, TOKEN_RETURN)) {
+    stmt->type = STATEMENT_RETURN;
+    stmt->statement_return = parse_statement_return(reader);
+  } else {
+    printf("token_type=%d\n", peek(reader).type);
+    fail("expected statement");
+  }
+
+  return stmt;
+}
diff --git a/parser.h b/parser.h
new file mode 100644
index 0000000..66df2e4
--- /dev/null
+++ b/parser.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include "lexer.h"
+#include "ast.h"
+
+struct token_reader {
+  bool have_token;
+  struct token token;
+  struct lexer_state lexer_state;
+};
+
+struct statement * parse_statement(struct token_reader * reader);
diff --git a/print_class b/print_class
new file mode 100755
index 0000000..7acecf9
Binary files /dev/null and b/print_class differ
diff --git a/printf.c b/printf.c
new file mode 100644
index 0000000..f174025
--- /dev/null
+++ b/printf.c
@@ -0,0 +1,186 @@
+#include <stdint.h>
+#include <stdarg.h>
+
+#include "string_parse.h"
+#include "string_unparse.h"
+#include "printf.h"
+//#include "sh7091_scif.h"
+
+enum format_type {
+  FORMAT_BASE10_UNSIGNED,
+  FORMAT_BASE10,
+  FORMAT_BASE10_64,
+  FORMAT_POINTER,
+  FORMAT_BASE16,
+  FORMAT_STRING,
+  FORMAT_CHAR,
+  FORMAT_PERCENT,
+};
+
+struct format {
+  enum format_type type;
+  int pad_length;
+  char fill_char;
+};
+
+static const char * parse_escape(const char * format, struct format * ft);
+
+static const char * parse_fill_pad(const char * format, struct format * ft)
+{
+  if (*format == 0)
+    return format;
+  if (*format >= '1' || *format <= '9')
+    ft->fill_char = ' ';
+  else
+    ft->fill_char = *format++;
+  format = parse_base10(format, &ft->pad_length);
+  return parse_escape(format, ft);
+}
+
+static const char * parse_escape(const char * format, struct format * ft)
+{
+  switch (*format) {
+  case 0:
+    return format;
+  case 'u':
+    ft->type = FORMAT_BASE10_UNSIGNED;
+    return format + 1;
+  case 'd':
+    ft->type = FORMAT_BASE10;
+    return format + 1;
+  case 'l':
+    ft->type = FORMAT_BASE10_64;
+    return format + 1;
+  case 'p':
+    ft->type = FORMAT_POINTER;
+    return format + 1;
+  case 'x':
+    ft->type = FORMAT_BASE16;
+    return format + 1;
+  case 's':
+    ft->type = FORMAT_STRING;
+    return format + 1;
+  case 'c':
+    ft->type = FORMAT_CHAR;
+    return format + 1;
+  case '%':
+    ft->type = FORMAT_PERCENT;
+    return format + 1;
+  default:
+    return parse_fill_pad(format, ft);
+  }
+}
+
+void print_string(const char * s, int length)
+{
+  for (int i = 0; i < length; i++) {
+    print_char(s[i]);
+  }
+}
+
+void print_bytes(const uint8_t * s, int length)
+{
+  for (int i = 0; i < length; i++) {
+    print_char(s[i]);
+  }
+}
+
+void print_chars(const uint16_t * s, int length)
+{
+  for (int i = 0; i < length; i++) {
+    print_char(s[i]);
+  }
+}
+
+void print_cstring(const char * s)
+{
+  while (*s != 0) {
+    print_char(*s++);
+  }
+}
+
+void _printf(const char * format, ...)
+{
+  va_list args;
+  va_start(args, format);
+
+  while (true) {
+    if (*format == 0)
+      break;
+
+    switch (*format) {
+    case '%':
+      {
+        struct format ft = {0};
+        format = parse_escape(format + 1, &ft);
+        switch (ft.type) {
+        case FORMAT_BASE10_UNSIGNED:
+          {
+            uint32_t num = va_arg(args, uint32_t);
+            char s[10];
+            int offset = unparse_base10_unsigned(s, num, ft.pad_length, ft.fill_char);
+            print_string(s, offset);
+          }
+          break;
+        case FORMAT_BASE10:
+          {
+            int32_t num = va_arg(args, int32_t);
+            char s[10];
+            int offset = unparse_base10(s, num, ft.pad_length, ft.fill_char);
+            print_string(s, offset);
+          }
+          break;
+        case FORMAT_BASE10_64:
+          {
+            int64_t num = va_arg(args, int64_t);
+            char s[20];
+            int offset = unparse_base10_64(s, num, ft.pad_length, ft.fill_char);
+            print_string(s, offset);
+          }
+          break;
+        case FORMAT_POINTER:
+          {
+            print_char('0');
+            print_char('x');
+          }
+          /* fall through */;
+        case FORMAT_BASE16:
+          {
+            uint32_t num = va_arg(args, uint32_t);
+            char s[8];
+            int offset = unparse_base16(s, num, ft.pad_length, ft.fill_char);
+            print_string(s, offset);
+          }
+          break;
+        case FORMAT_STRING:
+          {
+            const char * s = va_arg(args, const char *);
+            while (*s != 0) {
+              char c = *s++;
+              print_char(c);
+            }
+          }
+          break;
+        case FORMAT_CHAR:
+          {
+            const int c = va_arg(args, const int);
+            print_char((char)c);
+          }
+          break;
+        case FORMAT_PERCENT:
+          print_char('%');
+          break;
+        }
+      }
+      break;
+    default:
+      {
+        char c = *format++;
+        print_char(c);
+      }
+      break;
+    }
+  }
+
+  va_end(args);
+}
diff --git a/printf.h b/printf.h
new file mode 100644
index 0000000..1713fba
--- /dev/null
+++ b/printf.h
@@ -0,0 +1,47 @@
+#pragma once
+
+#if defined(__dreamcast__)
+#include "sh7091_scif.h"
+#else
+#include <stdio.h>
+#endif
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static inline void print_char(char c)
+{
+#if defined(__dreamcast__)
+  //  scif_character(c);
+#else
+  fputc(c, stderr);
+#endif
+}
+
+void print_string(const char * s, int length);
+void print_bytes(const uint8_t * s, int length);
+void print_chars(const uint16_t * s, int length);
+void print_cstring(const char * s);
+
+void _printf(const char * format, ...);
+
+#define printf(...) _printf(__VA_ARGS__)
+#define printc(c) print_char(c)
+#define prints(s) print_cstring(s)
+
+#if defined(DEBUG_PRINT)
+#define debugf(...) _printf(__VA_ARGS__)
+#define debugc(c) print_char(c)
+#define debugs(s) print_cstring(s)
+#else
+#define debugf(...)
+#define debugc(c)
+#define debugs(c)
+#endif
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/string_parse.c b/string_parse.c
new file mode 100644
index 0000000..05cb963
--- /dev/null
+++ b/string_parse.c
@@ -0,0 +1,70 @@
+#include <stddef.h>
+
+#include "string_parse.h"
+
+int parse_base10_digit(char c)
+{
+  switch (c) {
+  case '0': return 0;
+  case '1': return 1;
+  case '2': return 2;
+  case '3': return 3;
+  case '4': return 4;
+  case '5': return 5;
+  case '6': return 6;
+  case '7': return 7;
+  case '8': return 8;
+  case '9': return 9;
+  default: return -1;
+  }
+}
+
+const char * parse_base10(const char * s, int * n)
+{
+  *n = 0;
+  int sign = 1;
+
+  if (*s == '-') {
+    sign = -1;
+    s++;
+  }
+
+  while (true) {
+    int digit = parse_base10_digit(*s);
+    if (digit == -1)
+      break;
+
+    *n *= 10;
+    *n += digit;
+    s++;
+  }
+
+  *n *= sign;
+
+  return s;
+}
+
+const char * parse_base10_64(const char * s, int64_t * n)
+{
+  *n = 0;
+  int sign = 1;
+
+  if (*s == '-') {
+    sign = -1;
+    s++;
+  }
+
+  while (true) {
+    int digit = parse_base10_digit(*s);
+    if (digit == -1)
+      break;
+
+    *n *= 10;
+    *n += digit;
+    s++;
+  }
+
+  *n *= sign;
+
+  return s;
+}
diff --git a/string_parse.h b/string_parse.h
new file mode 100644
index 0000000..3e7f4e4
--- /dev/null
+++ b/string_parse.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+const char * parse_skip(const char * s, char c);
+const char * parse_find(const char * s, char c);
+const char * parse_find_first_right(const char * s, int length, char c);
+int parse_base10_digit(char c);
+const char * parse_base10(const char * s, int * n);
+const char * parse_base10_64(const char * s, int64_t * n);
+const char * parse_match(const char * s, const char * m);
+int parse_stride(const char * s, int length);
+int parse_height(const char * s, int length);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/string_unparse.c b/string_unparse.c
new file mode 100644
index 0000000..45a78fa
--- /dev/null
+++ b/string_unparse.c
@@ -0,0 +1,194 @@
+#include <stdint.h>
+
+#include "minmax.h"
+#include "string_unparse.h"
+
+int digits_base10(uint32_t n)
+{
+  if (n >= 1000000000ul) return 10;
+  if (n >= 100000000ul) return 9;
+  if (n >= 10000000ul) return 8;
+  if (n >= 1000000ul) return 7;
+  if (n >= 100000ul) return 6;
+  if (n >= 10000ul) return 5;
+  if (n >= 1000ul) return 4;
+  if (n >= 100ul) return 3;
+  if (n >= 10ul) return 2;
+  return 1;
+}
+
+int unparse_base10_unsigned(char * s, uint32_t n, int len, char fill)
+{
+  int digits = 0;
+  digits += digits_base10(n);
+  len = max(digits, len);
+  int ret = len;
+
+  while (len > digits) {
+    *s++ = fill;
+    --len;
+  }
+
+  while (len > 0) {
+    const uint32_t digit = n % 10;
+    n = n / 10;
+    s[--len] = digit + 48;
+  }
+
+  return ret;
+}
+
+int unparse_base10(char * s, int32_t n, int len, char fill)
+{
+  bool negative = false;
+  int digits = 0;
+  if (n < 0) {
+    digits += 1;
+    n = -n;
+    negative = true;
+  }
+
+  digits += digits_base10(n);
+  len = max(digits, len);
+  int ret = len;
+
+  while (len > digits) {
+    *s++ = fill;
+    --len;
+  }
+
+  if (negative) {
+    *s++ = '-';
+    len--;
+  }
+
+  while (len > 0) {
+    const uint32_t digit = n % 10;
+    n = n / 10;
+    s[--len] = digit + 48;
+  }
+
+  return ret;
+}
+
+int digits_base10_64(uint64_t n)
+{
+  if (n >= 10000000000000000000ull) return 20;
+  if (n >= 1000000000000000000ull) return 19;
+  if (n >= 100000000000000000ull) return 18;
+  if (n >= 10000000000000000ull) return 17;
+  if (n >= 1000000000000000ull) return 16;
+  if (n >= 100000000000000ull) return 15;
+  if (n >= 10000000000000ull) return 14;
+  if (n >= 1000000000000ull) return 13;
+  if (n >= 100000000000ull) return 12;
+  if (n >= 10000000000ull) return 11;
+  if (n >= 1000000000ull) return 10;
+  if (n >= 100000000ull) return 9;
+  if (n >= 10000000ull) return 8;
+  if (n >= 1000000ull) return 7;
+  if (n >= 100000ull) return 6;
+  if (n >= 10000ull) return 5;
+  if (n >= 1000ull) return 4;
+  if (n >= 100ull) return 3;
+  if (n >= 10ull) return 2;
+  return 1;
+}
+
+int unparse_base10_64(char * s, int64_t n, int len, char fill)
+{
+  bool negative = false;
+  int digits = 0;
+  if (n < 0) {
+    digits += 1;
+    n = -n;
+    negative = true;
+  }
+
+  digits += digits_base10_64(n);
+  len = max(digits, len);
+  int ret = len;
+
+  while (len > digits) {
+    *s++ = fill;
+    --len;
+  }
+
+  if (negative) {
+    *s++ = '-';
+    len--;
+  }
+
+  while (len > 0) {
+    const uint32_t digit = n % 10;
+    n = n / 10;
+    s[--len] = digit + 48;
+  }
+
+  return ret;
+}
+
+static int digits_base16(uint32_t n)
+{
+  if (n <= 0xf) return 1;
+  if (n <= 0xff) return 2;
+  if (n <= 0xfff) return 3;
+  if (n <= 0xffff) return 4;
+  if (n <= 0xfffff) return 5;
+  if (n <= 0xffffff) return 6;
+  if (n <= 0xfffffff) return 7;
+  return 8;
+}
+
+int unparse_base16(char * s, uint32_t n, int len, char fill)
+{
+  int digits = digits_base16(n);
+  len = max(digits, len);
+  int ret = len;
+
+  while (len > digits) {
+    *s++ = fill;
+    --len;
+  }
+
+  while (len > 0) {
+    uint32_t nib = n & 0xf;
+    n = n >> 4;
+    if (nib > 9) {
+      nib += (97 - 10);
+    } else {
+      nib += (48 - 0);
+    }
+
+    s[--len] = nib;
+  }
+
+  return ret;
+}
+
+#ifdef UNPARSE_TEST
+#include <stdio.h>
+
+int main()
+{
+  char s[1024];
+
+  {
+    int n = 124;
+
+    int offset = unparse_base10(s, n, 6, ' ');
+    s[offset] = 0;
+
+    printf("`%s`\n", s);
+  }
+
+  {
+    int n = 0x5678;
+
+    int offset = unparse_base16(s, n, 7, '0');
+    s[offset] = 0;
+
+    printf("`%s`\n", s);
+  }
+}
+#endif
diff --git a/string_unparse.h b/string_unparse.h
new file mode 100644
index 0000000..ba8ea99
--- /dev/null
+++ b/string_unparse.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int unparse_base10_unsigned(char * s, uint32_t n, int len, char fill);
+int unparse_base10(char * s, int32_t n, int len, char fill);
+int unparse_base10_64(char * s, int64_t n, int len, char fill);
+int unparse_base16(char * s, uint32_t n, int len, char fill);
+
+int digits_base_64(uint64_t n);
+int digits_base10_64(uint64_t n);
+
+#ifdef __cplusplus
+}
+#endif