chapter 1: ex2

.gitignore

@@ -1,2 +1,4 @@
 .direnv
 .ccls-cache
+a.out
+*.o

c1/compile_commands.json

@@ -8,35 +8,5 @@
     ],
     "directory": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1",
     "file": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1/main.c"
-  },
-  {
-    "arguments": [
-      "/nix/store/k8mrxviw965lv59hqbln3297jwfffm2w-clang-wrapper-16.0.6/bin/clang",
-      "-g",
-      "-c",
-      "prog1.c"
-    ],
-    "directory": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1",
-    "file": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1/prog1.c"
-  },
-  {
-    "arguments": [
-      "/nix/store/k8mrxviw965lv59hqbln3297jwfffm2w-clang-wrapper-16.0.6/bin/clang",
-      "-g",
-      "-c",
-      "slp.c"
-    ],
-    "directory": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1",
-    "file": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1/slp.c"
-  },
-  {
-    "arguments": [
-      "/nix/store/k8mrxviw965lv59hqbln3297jwfffm2w-clang-wrapper-16.0.6/bin/clang",
-      "-g",
-      "-c",
-      "util.c"
-    ],
-    "directory": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1",
-    "file": "/Users/mthomson/dev/personal/modern-compiler-implementation-in-c/c1/util.c"
   }
 ]

c1/main.c

@@ -1,7 +1,9 @@
 #include <math.h>
 #include <stdio.h>
+#include <strings.h>
 
 #include "prog1.h"
+#include "main.h"
 
 int maxargs(A_stm statement)
 {
@@ -31,9 +33,88 @@ int maxargs(A_stm statement)
 	return 0;
 }
 
+Table_ interpStm(A_stm stm, Table_ t) {
+  if (stm->kind == A_compoundStm) {
+    t = interpStm(stm->u.compound.stm1, t);
+    t = interpStm(stm->u.compound.stm2, t);
+  } else if (stm->kind == A_assignStm) {
+    IntAndTable_ it = interpExp(stm->u.assign.exp, t);
+    t = Table(stm->u.assign.id, it->i, it->t);
+  } else {
+    A_expList expList = stm->u.print.exps;
+    while (expList->kind != A_lastExpList) {
+      t = interpExp(expList->u.pair.head, t)->t;
+      expList = expList->u.pair.tail;
+    }
+    t = interpExp(expList->u.last, t)->t;
+  }
+
+  return t;
+}
+
+IntAndTable_ interpExp(A_exp e, Table_ t) {
+  if (e->kind == A_idExp) {
+    return IntAndTable(lookup(t, e->u.id), t);
+  } else if (e->kind == A_numExp) {
+    return IntAndTable(e->u.num, t);
+  } else if (e->kind == A_opExp) {
+    IntAndTable_ left = interpExp(e->u.op.left, t);
+    IntAndTable_ right = interpExp(e->u.op.right, t);
+    A_binop op = e->u.op.oper;
+
+    switch (op) {
+    case A_plus:
+      return IntAndTable(left->i + right->i, t);
+    case A_minus:
+      return IntAndTable(left->i - right->i, t);
+    case A_times:
+      return IntAndTable(left->i * right->i, t);
+    case A_div:
+      return IntAndTable(left->i / right->i, t);
+    }
+  } else {
+    t = interpStm(e->u.eseq.stm, t);
+    return interpExp(e->u.eseq.exp, t);
+  }
+}
+
+IntAndTable_ IntAndTable(int i, Table_ t) {
+  IntAndTable_ it = checked_malloc(sizeof(*it));
+  it->i = i;
+  it->t = t;
+  return it;
+}
+
+Table_ Table(string id, int value, struct table *tail) {
+  Table_ t = checked_malloc(sizeof(*t));
+  t->id = id;
+  t->value = value;
+  t->tail = tail;
+  return t;
+}
+
+int lookup(Table_ t, string key) {
+  if (t == NULL) {
+    // HACK: should indicate a null value
+    return 0;
+  }
+
+  if (strcmp(t->id, key) == 0) {
+    return t->value;
+  }
+
+  return lookup(t->tail, key);
+}
+
 int main()
 {
 	A_stm program = prog();
 	int result = maxargs(program);
   printf("maxargs: %d\n", result);
+
+  Table_ t = interpStm(program, NULL);
+
+
+  printf("a: %d\n", lookup(t, "a"));
+  printf("b: %d\n", lookup(t, "b"));
 }

c1/main.h

@@ -0,0 +1,20 @@
+#ifndef MAIN_H
+#define MAIN_H
+
+#include "util.h"
+#include "slp.h"
+
+typedef struct table *Table_;
+struct table {string id; int value; Table_ tail;};
+Table_ Table(string id, int value, struct table *tail);
+
+Table_ interpStm(A_stm s, Table_ t);
+
+int lookup(Table_ t, string key);
+
+typedef struct intandtable *IntAndTable_;
+struct intandtable {int i; Table_ t;};
+IntAndTable_ IntAndTable(int i, Table_ t);
+IntAndTable_ interpExp(A_exp e, Table_ t);
+
+#endif // !MAIN_H

c1/makefile

@@ -1,7 +1,7 @@
 a.out: main.o prog1.o slp.o util.o
 	cc -g main.o prog1.o slp.o util.o
 
-main.o: main.c slp.h util.h
+main.o: main.c slp.h util.h main.h
 	cc -g -c main.c
 
 prog1.o: prog1.c slp.h util.h

c1/util.c

@@ -1,5 +1,12 @@
 #include <stdlib.h>
+#include <strings.h>
 #include "util.h"
+string String(char *s)
+{
+  string p = checked_malloc(strlen(s)+1);
+  strcpy(p,s);
+  return p;
+}
 
 void *checked_malloc(int len)
 {

compile_commands.json

@@ -0,0 +1 @@
+[]