initial

1 files changed, 48 insertions, 0 deletions

diff --git a/bootstrap/env.c b/bootstrap/env.c
new file mode 100644
index 0000000..513b4d9
--- /dev/null
+++ b/bootstrap/env.c
@@ -0,0 +1,48 @@
+#include "all.h"
+
+
+struct decl *
+envfind(const struct env *env, const char *name) {
+   if (!env)
+      return NULL;
+   for (struct decls *decls = env->decls; decls; decls = decls->next) {
+      if (!strcmp(decls->decl.name, name))
+         return &decls->decl;
+   }
+   return envfind(env->parent, name);
+}
+
+static bool
+declsshadowable(const struct decl *a, const struct decl *b) {
+   return b->t == Dvar;
+}
+
+static bool
+declscompatible(const struct decl *a, const struct decl *b) {
+   if (a->t != b->t)
+      return 0;
+   if (a->t == Dfn && a->fn.selfty == b->fn.selfty && !a->fn.body)
+      return 1;
+   if (a->t == Dtype && a->ty == b->ty)
+      return 1;
+   return 0;
+}
+
+bool
+envput(struct env *env, const struct decl *decl) {
+   struct decls *decls;
+   struct env env_noparent = {
+     .decls = env->decls
+   };
+   struct decl *decl0;
+   if ((decl0 = envfind(&env_noparent, decl->name))) {
+      if (!declsshadowable(decl0, decl) && !declscompatible(decl0, decl))
+         return 0;
+   }
+
+   decls = xcalloc(1, sizeof *decls);
+   decls->next = env->decls;
+   decls->decl = *decl;
+   env->decls = decls;
+   return 1;
+}