From f6c8cac5c77f75766dbdbbb6d130a8d1835e2d68 Mon Sep 17 00:00:00 2001
From: Matthias Schuetz <mschuetz@gmail.com>
Date: Sun, 24 Feb 2008 23:58:15 +0000
Subject: [PATCH] basic lisp interpreter in c

git-svn-id: https://shell.noname-ev.de/svn/lisp/tinylisp@5 f9497395-c7e6-438d-86fc-c13047f9afa0
---
 Makefile        | 18 +++++++++++++
 base.c          | 70 +++++++++++++++++++++++++++++++++++++++++++++++++
 base.h          | 26 ++++++++++++++++++
 lisp_scanner.rl | 21 +++++++++++++++
 list.c          |  5 ++++
 list.h          |  5 ++++
 symbol_table.c  | 36 +++++++++++++++++++++++++
 symbol_table.h  | 19 ++++++++++++++
 test_scanner.c  |  5 ++++
 tinylisp.c      | 14 ++++++++++
 10 files changed, 219 insertions(+)
 create mode 100644 Makefile
 create mode 100644 base.c
 create mode 100644 base.h
 create mode 100644 lisp_scanner.rl
 create mode 100644 list.c
 create mode 100644 list.h
 create mode 100644 symbol_table.c
 create mode 100644 symbol_table.h
 create mode 100644 test_scanner.c
 create mode 100644 tinylisp.c

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..a060040
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,18 @@
+flex:
+	flex lisp_scanner.rl
+
+.c.o:
+	$(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) -c $<
+
+tinylisp: tinylisp.o symbol_table.o base.o
+	$(CC) -o tinylisp tinylisp.o symbol_table.o base.o
+
+
+run: tinylisp
+	./tinylisp
+
+clean: 
+	rm tinylisp *.o
+
+test: flex test_scanner.o lex.yy.o
+	gcc -o test_scanner test_scanner.o lex.yy.o /opt/local/lib/libfl.a
diff --git a/base.c b/base.c
new file mode 100644
index 0000000..f57b61a
--- /dev/null
+++ b/base.c
@@ -0,0 +1,70 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include "base.h"
+#include "symbol_table.h"
+
+struct object * car(struct cons_cell * cc){
+  return cc->car;
+}
+
+struct object * cdr(struct cons_cell * cc){
+  return cc->cdr;
+}
+
+bool atom_p(struct object * o){
+  return o!=nil && o->atom_p;
+}
+
+struct object * cons(struct object * o1, struct object * o2){
+  struct object * o = (struct object *) malloc(sizeof(struct object));
+  o->atom_p = false;
+  struct cons_cell * cc = (struct cons_cell *) malloc(sizeof(struct cons_cell));
+  o->data = cc;
+  cc->car = o1;
+  cc->cdr = o2;
+  return o;
+}
+
+struct object * quote(char * s){
+  return st_insert(s);
+}
+
+void print_cons(struct cons_cell * cc);
+void print_atom(atom a);
+
+void print(struct object * o){
+  if (o==nil) {
+    printf("nil");
+    return;
+  }
+
+  if (o->atom_p)
+    print_atom((atom) o->data);
+  else
+    print_cons((struct cons_cell *) o->data);
+}
+
+void print_cons(struct cons_cell * cc){
+  printf("(");
+  print(car(cc));
+
+  if (atom_p(cdr(cc))) {
+    printf(" . ");
+    print(cdr(cc));
+  } else {
+    
+  }
+
+  printf(")");
+}
+
+void print_atom(atom a){
+  printf("%s", st_id_to_name(a));
+}
+
+struct obj * read(){
+  char *s;
+  while(s = (char *)yylex())
+}
+
diff --git a/base.h b/base.h
new file mode 100644
index 0000000..1e3ad5a
--- /dev/null
+++ b/base.h
@@ -0,0 +1,26 @@
+#ifndef __TINYLISP_H
+#define __TINYLISP_H
+
+#include <stdbool.h>
+
+typedef int atom;
+
+#define nil NULL
+
+struct object {
+  bool atom_p;
+  void * data;
+};
+
+struct cons_cell {
+  struct object * car;
+  struct object * cdr;
+};
+
+struct object * car(struct cons_cell * cc);
+struct object * cdr(struct cons_cell * cc);
+struct object * quote(char * s);
+struct object * cons(struct object * o1, struct object * o2);
+void print(struct object * o);
+
+#endif
diff --git a/lisp_scanner.rl b/lisp_scanner.rl
new file mode 100644
index 0000000..6a5902f
--- /dev/null
+++ b/lisp_scanner.rl
@@ -0,0 +1,21 @@
+%{
+
+%}
+
+digit   [0-9]
+blank   [ \t]
+name1   [A-Za-z]
+name2   [A-Za-z_0-9]
+
+%%
+
+{name1}{name2}*         { return (char *)yytext; }
+
+
+"(" {return (char *)yytext;}
+")" {return (char *)yytext;}
+
+"\n"                    { }
+			
+{blank}+                ;
+%%
diff --git a/list.c b/list.c
new file mode 100644
index 0000000..e3cf161
--- /dev/null
+++ b/list.c
@@ -0,0 +1,5 @@
+#include "list.h"
+
+void * car(struct cons_cell * cons_cell){
+  return cons_cell->car
+}
diff --git a/list.h b/list.h
new file mode 100644
index 0000000..7e8721a
--- /dev/null
+++ b/list.h
@@ -0,0 +1,5 @@
+#ifndef __LIST_H
+#define __LIST_H
+
+
+#endif
diff --git a/symbol_table.c b/symbol_table.c
new file mode 100644
index 0000000..ae53fd9
--- /dev/null
+++ b/symbol_table.c
@@ -0,0 +1,36 @@
+#include <string.h>
+#include "symbol_table.h"
+
+static struct symbol_table st;
+
+struct object * st_insert(char * name){
+  struct object * o;
+  if ((o = st_lookup(name)) != NULL)
+    return o;
+
+  struct symbol * sym = &st.symbols[st.size];
+  o = &sym->object;
+  o->atom_p = true;
+  o->data = (void *)st.size;
+
+  int length = strlen(name);
+  strncpy(sym->name, name, length);
+
+  st.size++;
+  return o;
+}
+
+struct object * st_lookup(char * name){
+  int i;
+  for (i=0; i<st.size; i++){
+    if (strcmp(name, st.symbols[i].name) == 0)
+      return &st.symbols[i].object;
+  }
+  return NULL;
+}
+
+char * st_id_to_name(atom id){
+  return st.symbols[id].name;
+}
+
+
diff --git a/symbol_table.h b/symbol_table.h
new file mode 100644
index 0000000..0255360
--- /dev/null
+++ b/symbol_table.h
@@ -0,0 +1,19 @@
+#ifndef __SYMBOL_TABLE_H
+#define __SYMBOL_TABLE_H
+
+#include "base.h"
+struct symbol {
+  struct object object;
+  char name[128];
+};
+
+struct symbol_table {
+  struct symbol symbols[2048];
+  int size;
+};
+
+struct object * st_insert(char * name);
+struct object * st_lookup(char * name);
+char * st_id_to_name(int id);
+
+#endif
diff --git a/test_scanner.c b/test_scanner.c
new file mode 100644
index 0000000..2679585
--- /dev/null
+++ b/test_scanner.c
@@ -0,0 +1,5 @@
+int main(){
+  char * sym;
+  while (sym = (char *)yylex())
+    printf("got >%s<\n", sym);
+}
diff --git a/tinylisp.c b/tinylisp.c
new file mode 100644
index 0000000..dcf249e
--- /dev/null
+++ b/tinylisp.c
@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include "base.h"
+#include "symbol_table.h"
+
+int main(int argc, char **argv){
+  st_insert("nil");
+  st_insert("t");
+  struct object * list;
+  list = cons(quote("a"), cons(quote("b"), cons(quote("c"), nil)));
+  print(cons(quote("a"), quote("b"))); puts("");
+  print(list);
+  return 0;
+}
+