Get basic G-machine compilation working.

src/compiler.cpp

@@ -0,0 +1,30 @@
+#include "compiler.hpp"
+#include "error.hpp"
+
+namespace lily {
+    void compile_env::set_parent(std::shared_ptr<compile_env> p) {
+        parent = p;
+    }
+
+    int compile_env_var::get_offset(const std::string& name) {
+        if(this->var == name) return 0;
+        if(parent) return parent->get_offset(name) + 1;
+        throw error("unknown variable name");
+    }
+
+    bool compile_env_var::is_variable(const std::string& name) {
+        if(this->var == name) return true;
+        if(parent) return parent->is_variable(name);
+        return false;
+    }
+
+    int compile_env_offset::get_offset(const std::string& name) {
+        if(parent) return parent->get_offset(name) + offset;
+        throw error("unknown variable name");
+    }
+
+    bool compile_env_offset::is_variable(const std::string& name) {
+        if(parent) return parent->is_variable(name);
+        return false;
+    }
+}