diff --git a/Cargo.lock b/Cargo.lock
index df746ea10..f328e2b5d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -752,6 +752,7 @@ dependencies = [
  "cranelift-wasm 0.22.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "docopt 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
  "libffi 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "memmap 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/Cargo.toml b/Cargo.toml
index 7e6793954..ea098bdf2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,7 +3,7 @@ name = "wasmer"
 version = "0.1.0"
 authors = ["Syrus Akbary <me@syrusakbary.com>"]
 edition = "2018"
-repository = "https://github.com/wapmio/wasmer"
+repository = "https://github.com/wafoundation/wasmer"
 publish = false
 
 [dependencies]
@@ -28,9 +28,11 @@ memmap = "0.6.2"
 spin = "0.4.9"
 log = "0.4.5"
 target-lexicon = { version = "0.0.3", default-features = false }
+libc = "0.2"
 
 [dev-dependencies]
 libffi = "0.6.4"
+# maplit = "1.0.1"
 
 [features]
 debug = []
diff --git a/src/integrations/mod.rs b/src/integrations/mod.rs
new file mode 100644
index 000000000..5f1e13b6d
--- /dev/null
+++ b/src/integrations/mod.rs
@@ -0,0 +1,27 @@
+use libc::putchar;
+
+#[cfg(test)]
+mod tests {
+    use crate::webassembly::{
+        instantiate, ErrorKind, Export, ImportObject, Instance, Module, ResultObject,
+    };
+    use libc::putchar;
+
+    #[test]
+    fn test_putchar() {
+        let wasm_bytes = include_wast2wasm_bytes!("tests/putchar.wast");
+        let mut import_object = ImportObject::new();
+        import_object.set("env", "putchar", putchar as *const u8);
+
+        let result_object =
+            instantiate(wasm_bytes, Some(import_object)).expect("Not compiled properly");
+        let module = result_object.module;
+        let instance = result_object.instance;
+        let func_index = match module.info.exports.get("main") {
+            Some(&Export::Function(index)) => index,
+            _ => panic!("Function not found"),
+        };
+        let main: fn() = get_instance_function!(instance, func_index);
+        main();
+    }
+}
diff --git a/src/integrations/tests/putchar.wast b/src/integrations/tests/putchar.wast
new file mode 100644
index 000000000..d61d6ada0
--- /dev/null
+++ b/src/integrations/tests/putchar.wast
@@ -0,0 +1,16 @@
+(module
+ (type $FUNCSIG$ii (func (param i32) (result i32)))
+ (import "env" "putchar" (func $putchar (param i32) (result i32)))
+ (table 0 anyfunc)
+ (memory $0 1)
+ (export "memory" (memory $0))
+ (export "main" (func $main))
+ (func $main (; 1 ;) (result i32)
+  (drop
+   (call $putchar
+    (i32.const 97)
+   )
+  )
+  (i32.const 0)
+ )
+)
diff --git a/src/macros.rs b/src/macros.rs
index e09dae517..beda68363 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -9,6 +9,14 @@ macro_rules! get_instance_function {
     }};
 }
 
+macro_rules! include_wast2wasm_bytes {
+    ($x:expr) => {{
+        use wabt::wat2wasm;
+        const wast_bytes: &[u8] = include_bytes!($x);
+        wat2wasm(wast_bytes.to_vec()).expect(&format!("Can't convert {} file to wasm", $x))
+    }};
+}
+
 // #[cfg(feature = "debug")]
 #[macro_export]
 macro_rules! debug {
diff --git a/src/main.rs b/src/main.rs
index 463b9b9f6..ec3d4be3f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,4 @@
-#![feature(test)]
+#![feature(test, libc)]
 
 extern crate test;
 #[macro_use]
@@ -18,6 +18,7 @@ use std::time::{Duration, Instant};
 
 // #[macro_use] extern crate log;
 
+use libc;
 use std::error::Error;
 use std::fs::File;
 use std::io;
@@ -31,6 +32,7 @@ use wabt::wat2wasm;
 #[macro_use]
 mod macros;
 pub mod common;
+pub mod integrations;
 pub mod spec;
 pub mod webassembly;
 
diff --git a/src/spec/tests.rs b/src/spec/tests.rs
index ba74baf65..e543bdf06 100644
--- a/src/spec/tests.rs
+++ b/src/spec/tests.rs
@@ -12,7 +12,7 @@ use wabt::script::{Action, Value};
 
 use super::{run_single_file, InvokationResult, ScriptHandler};
 use crate::webassembly::{
-    compile, instantiate, Error, ErrorKind, Export, Instance, Module, ResultObject,
+    compile, instantiate, Error, ErrorKind, Export, ImportObject, Instance, Module, ResultObject,
 };
 
 struct StoreCtrl<'module> {
@@ -127,18 +127,15 @@ impl<'module> ScriptHandler for StoreCtrl<'module> {
         unimplemented!()
     }
     fn module(&mut self, bytes: Vec<u8>, name: Option<String>) {
-        let mut import_object = HashMap::new();
-        let mut test_import = import_object
-            .entry("test".to_string())
-            .or_insert_with(|| HashMap::new());
-        fn identity(x: i32) -> i32 {
+        let mut import_object = ImportObject::new();
+        extern "C" fn identity(x: i32) -> i32 {
             x
         };
-        test_import.insert("identity".to_string(), identity as *const u8);
+        import_object.set("test", "identity", identity as *const u8);
         // let import_object = import_object!{
         //     test.identity => fn(x: i32) {x},
         // }
-        let module_wrapped = instantiate(bytes, Some(&import_object));
+        let module_wrapped = instantiate(bytes, Some(import_object));
         let mut result = module_wrapped.expect("Module is invalid");
         // let module: &'module Module = result.module;
         self.last_module = Some(result);
@@ -211,8 +208,7 @@ mod tests {
 
     macro_rules! instantiate_from_wast {
         ($x:expr) => {{
-            pub const WAST_BYTES: &[u8] = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), $x));
-            let wasm_bytes = wat2wasm(WAST_BYTES.to_vec()).expect("Can't convert wat to wasm");
+            let wasm_bytes = include_wast2wasm_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), $x));
             let result_object = instantiate(wasm_bytes, None).expect("Not compiled properly");
             result_object
         }};
diff --git a/src/webassembly/import_object.rs b/src/webassembly/import_object.rs
new file mode 100644
index 000000000..cf3db5de1
--- /dev/null
+++ b/src/webassembly/import_object.rs
@@ -0,0 +1,136 @@
+use std::borrow::Borrow;
+use std::collections::HashMap;
+use std::hash::{Hash, Hasher};
+
+// See explanation (1).
+#[derive(PartialEq, Eq, Hash)]
+struct Pair<A, B>(A, B);
+
+#[derive(PartialEq, Eq, Hash)]
+struct BorrowedPair<'a, 'b, A: 'a, B: 'b>(&'a A, &'b B);
+
+// See explanation (2).
+trait KeyPair<A, B> {
+    /// Obtains the first element of the pair.
+    fn a(&self) -> &A;
+    /// Obtains the second element of the pair.
+    fn b(&self) -> &B;
+}
+
+// See explanation (3).
+impl<'a, A, B> Borrow<KeyPair<A, B> + 'a> for Pair<A, B>
+where
+    A: Eq + Hash + 'a,
+    B: Eq + Hash + 'a,
+{
+    fn borrow(&self) -> &(KeyPair<A, B> + 'a) {
+        self
+    }
+}
+
+// See explanation (4).
+impl<'a, A: Hash, B: Hash> Hash for (KeyPair<A, B> + 'a) {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.a().hash(state);
+        self.b().hash(state);
+    }
+}
+
+impl<'a, A: Eq, B: Eq> PartialEq for (KeyPair<A, B> + 'a) {
+    fn eq(&self, other: &Self) -> bool {
+        self.a() == other.a() && self.b() == other.b()
+    }
+}
+
+impl<'a, A: Eq, B: Eq> Eq for (KeyPair<A, B> + 'a) {}
+
+// OP's ImportObject struct
+pub struct ImportObject<A: Eq + Hash, B: Eq + Hash> {
+    map: HashMap<Pair<A, B>, *const u8>,
+}
+
+impl<A: Eq + Hash, B: Eq + Hash> ImportObject<A, B> {
+    pub fn new() -> Self {
+        ImportObject {
+            map: HashMap::new(),
+        }
+    }
+
+    pub fn get(&self, a: &A, b: &B) -> Option<*const u8> {
+        self.map
+            .get(&BorrowedPair(a, b) as &KeyPair<A, B>)
+            .map(|p| *p)
+    }
+
+    pub fn set(&mut self, a: A, b: B, v: *const u8) {
+        self.map.insert(Pair(a, b), v);
+    }
+}
+
+// pub struct ImportObject<A: Eq + Hash, B: Eq + Hash> {
+//     map: HashMap<Pair<A, B>, *const u8>,
+// }
+
+// impl<A: Eq + Hash, B: Eq + Hash> ImportObject<A, B> {
+//     pub fn new() -> Self {
+//         ImportObject { map: HashMap::new() }
+//     }
+
+//     pub fn get(&self, a: &A, b: &B) -> *const u8 {
+//         *self.map.get(&BorrowedPair(a, b) as &KeyPair<A, B>).unwrap()
+//     }
+
+//     pub fn set(&mut self, a: A, b: B, v: *const u8) {
+//         self.map.insert(Pair(a, b), v);
+//     }
+// }
+// Boring stuff below.
+
+impl<A, B> KeyPair<A, B> for Pair<A, B>
+where
+    A: Eq + Hash,
+    B: Eq + Hash,
+{
+    fn a(&self) -> &A {
+        &self.0
+    }
+    fn b(&self) -> &B {
+        &self.1
+    }
+}
+impl<'a, 'b, A, B> KeyPair<A, B> for BorrowedPair<'a, 'b, A, B>
+where
+    A: Eq + Hash + 'a,
+    B: Eq + Hash + 'b,
+{
+    fn a(&self) -> &A {
+        self.0
+    }
+    fn b(&self) -> &B {
+        self.1
+    }
+}
+
+//----------------------------------------------------------------
+
+// #[derive(Eq, PartialEq, Hash)]
+// struct A(&'static str);
+
+// #[derive(Eq, PartialEq, Hash)]
+// struct B(&'static str);
+
+#[cfg(test)]
+mod tests {
+    use super::ImportObject;
+
+    #[test]
+    fn test_import_object() {
+        fn x() {}
+        let mut import_object = ImportObject::new();
+        import_object.set("abc", "def", x as *const u8);
+        // import_object.set("123"), A("456"), 45.0);
+        assert_eq!(import_object.get(&"abc", &"def").unwrap(), x as *const u8);
+        // assert_eq!(import_object.get(&"abc", &"dxf"), 4.0);
+        // assert_eq!(import_object.get(&A("123"), &A("456")), 45.0);
+    }
+}
diff --git a/src/webassembly/instance.rs b/src/webassembly/instance.rs
index ec27d9c6d..8e70dcb3f 100644
--- a/src/webassembly/instance.rs
+++ b/src/webassembly/instance.rs
@@ -21,6 +21,7 @@ use std::{mem, slice};
 
 use super::super::common::slice::{BoundedSlice, UncheckedSlice};
 use super::errors::ErrorKind;
+use super::import_object::ImportObject;
 use super::memory::LinearMemory;
 use super::module::Module;
 use super::module::{DataInitializer, Export, Exportable};
@@ -99,9 +100,6 @@ pub struct UserData {
     pub instance: Instance,
 }
 
-// The import object for the instance
-pub type ImportObject = HashMap<String, HashMap<String, *const u8>>;
-
 /// An Instance of a WebAssembly module
 #[derive(Debug)]
 pub struct Instance {
@@ -157,7 +155,7 @@ impl Instance {
     /// Create a new `Instance`.
     pub fn new(
         module: &Module,
-        import_object: Option<&ImportObject>,
+        import_object: &ImportObject<&str, &str>,
     ) -> Result<Instance, ErrorKind> {
         let mut tables: Vec<Vec<usize>> = Vec::new();
         let mut memories: Vec<LinearMemory> = Vec::new();
@@ -178,14 +176,15 @@ impl Instance {
             // let mut context_and_offsets = Vec::with_capacity(module.info.function_bodies.len());
             for (module, field) in module.info.imported_funcs.iter() {
                 // let function = &import_object.map(|i| i.get(module).map(|m| m.get(field)));
-                let mut function = fake_fun as *const u8;
-                if let Some(import_object) = import_object {
-                    if let Some(module) = import_object.get(module) {
-                        if let Some(field_function) = module.get(field) {
-                            function = *field_function;
-                        }
-                    }
-                }
+                // let mut function = fake_fun as *const u8;
+                let mut function = import_object
+                    .get(&module.as_str(), &field.as_str())
+                    .ok_or_else(|| {
+                        ErrorKind::LinkError(format!(
+                            "Imported function {}.{} was not provided in the import_functions",
+                            module, field
+                        ))
+                    })?;
                 // println!("GET FUNC {:?}", function);
                 import_functions.push(function);
                 relocations.push(vec![]);
@@ -444,8 +443,7 @@ impl Instance {
         self.memories.clone()
     }
     pub fn get_function_pointer(&self, func_index: FuncIndex) -> *const u8 {
-        let func_pointer = &self.functions[func_index.index()];
-        func_pointer.as_ptr()
+        get_function_addr(&func_index, &self.import_functions, &self.functions)
     }
 
     // pub fn is_imported_function(&self, func_index: FuncIndex) -> bool {
diff --git a/src/webassembly/mod.rs b/src/webassembly/mod.rs
index 5fbe64024..439b32850 100644
--- a/src/webassembly/mod.rs
+++ b/src/webassembly/mod.rs
@@ -1,4 +1,5 @@
 pub mod errors;
+pub mod import_object;
 pub mod instance;
 pub mod memory;
 pub mod module;
@@ -14,7 +15,8 @@ use target_lexicon::{self, Triple};
 use wasmparser;
 
 pub use self::errors::{Error, ErrorKind};
-pub use self::instance::{ImportObject, Instance};
+pub use self::import_object::ImportObject;
+pub use self::instance::Instance;
 pub use self::memory::LinearMemory;
 pub use self::module::{Export, Module, ModuleInfo};
 
@@ -43,11 +45,15 @@ pub struct ResultObject {
 /// webassembly::RuntimeError, depending on the cause of the failure.
 pub fn instantiate(
     buffer_source: Vec<u8>,
-    import_object: Option<&ImportObject>,
+    import_object: Option<ImportObject<&str, &str>>,
 ) -> Result<ResultObject, ErrorKind> {
     let module = compile(buffer_source)?;
     debug!("webassembly - creating instance");
-    let instance = Instance::new(&module, import_object)?;
+    let import_object: ImportObject<&str, &str> = match import_object {
+        Some(import_object) => import_object,
+        None => ImportObject::new(),
+    };
+    let instance = Instance::new(&module, &import_object)?;
     debug!("webassembly - instance created");
     Ok(ResultObject { module, instance })
 }