diff --git a/src/protocol/ast.rs b/src/protocol/ast.rs
index e137985fa110c6e2cea9a0f83be7cedf79aef88d..3bcc0b525893c980586cd57246693feb65892865 100644
--- a/src/protocol/ast.rs
+++ b/src/protocol/ast.rs
@@ -242,7 +242,7 @@ pub struct Root {
 }
 
 impl Root {
-    pub fn get_definition_ident(&self, h: &Heap, id: &[u8]) -> Option<DefinitionId> {
+    pub fn get_definition_by_ident(&self, h: &Heap, id: &[u8]) -> Option<DefinitionId> {
         for &def in self.definitions.iter() {
             if h[def].identifier().value.as_bytes() == id {
                 return Some(def);
@@ -932,7 +932,6 @@ pub struct StructDefinition {
     pub this: StructDefinitionId,
     pub defined_in: RootId,
     // Symbol scanning
-    pub span: InputSpan,
     pub identifier: Identifier,
     pub poly_vars: Vec<Identifier>,
     // Parsing
@@ -941,10 +940,10 @@ pub struct StructDefinition {
 
 impl StructDefinition {
     pub(crate) fn new_empty(
-        this: StructDefinitionId, defined_in: RootId, span: InputSpan,
+        this: StructDefinitionId, defined_in: RootId,
         identifier: Identifier, poly_vars: Vec<Identifier>
     ) -> Self {
-        Self{ this, defined_in, span, identifier, poly_vars, fields: Vec::new() }
+        Self{ this, defined_in, identifier, poly_vars, fields: Vec::new() }
     }
 }
 
@@ -965,7 +964,6 @@ pub struct EnumDefinition {
     pub this: EnumDefinitionId,
     pub defined_in: RootId,
     // Symbol scanning
-    pub span: InputSpan,
     pub identifier: Identifier,
     pub poly_vars: Vec<Identifier>,
     // Parsing
@@ -974,10 +972,10 @@ pub struct EnumDefinition {
 
 impl EnumDefinition {
     pub(crate) fn new_empty(
-        this: EnumDefinitionId, defined_in: RootId, span: InputSpan,
+        this: EnumDefinitionId, defined_in: RootId,
         identifier: Identifier, poly_vars: Vec<Identifier>
     ) -> Self {
-        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
+        Self{ this, defined_in, identifier, poly_vars, variants: Vec::new() }
     }
 }
 
@@ -993,7 +991,6 @@ pub struct UnionDefinition {
     pub this: UnionDefinitionId,
     pub defined_in: RootId,
     // Phase 1: symbol scanning
-    pub span: InputSpan,
     pub identifier: Identifier,
     pub poly_vars: Vec<Identifier>,
     // Phase 2: parsing
@@ -1002,10 +999,10 @@ pub struct UnionDefinition {
 
 impl UnionDefinition {
     pub(crate) fn new_empty(
-        this: UnionDefinitionId, defined_in: RootId, span: InputSpan,
+        this: UnionDefinitionId, defined_in: RootId,
         identifier: Identifier, poly_vars: Vec<Identifier>
     ) -> Self {
-        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
+        Self{ this, defined_in, identifier, poly_vars, variants: Vec::new() }
     }
 }
 
@@ -1071,6 +1068,37 @@ impl ExpressionInfoVariant {
     }
 }
 
+#[derive(Debug)]
+pub enum ProcedureSource {
+    FuncUserDefined,
+    CompUserDefined,
+    // Builtin functions, available to user
+    FuncGet,
+    FuncPut,
+    FuncFires,
+    FuncCreate,
+    FuncLength,
+    FuncAssert,
+    FuncPrint,
+    // Buitlin functions, not available to user
+    FuncSelectStart,
+    FuncSelectRegisterCasePort,
+    FuncSelectWait,
+    // Builtin components, available to user
+    CompRandomU32, // TODO: Remove, temporary thing
+    CompTcpClient,
+}
+
+impl ProcedureSource {
+    pub(crate) fn is_builtin(&self) -> bool {
+        match self {
+            ProcedureSource::FuncUserDefined | ProcedureSource::CompUserDefined => false,
+            _ => true,
+        }
+    }
+}
+
+
 /// Generic storage for functions, primitive components and composite
 /// components.
 // Note that we will have function definitions for builtin functions as well. In
@@ -1080,12 +1108,11 @@ pub struct ProcedureDefinition {
     pub this: ProcedureDefinitionId,
     pub defined_in: RootId,
     // Symbol scanning
-    pub builtin: bool,
     pub kind: ProcedureKind,
-    pub span: InputSpan,
     pub identifier: Identifier,
     pub poly_vars: Vec<Identifier>,
     // Parser
+    pub source: ProcedureSource,
     pub return_type: Option<ParserType>, // present on functions, not components
     pub parameters: Vec<VariableId>,
     pub scope: ScopeId,
@@ -1096,14 +1123,13 @@ pub struct ProcedureDefinition {
 
 impl ProcedureDefinition {
     pub(crate) fn new_empty(
-        this: ProcedureDefinitionId, defined_in: RootId, span: InputSpan,
+        this: ProcedureDefinitionId, defined_in: RootId,
         kind: ProcedureKind, identifier: Identifier, poly_vars: Vec<Identifier>
     ) -> Self {
         Self {
             this, defined_in,
-            builtin: false,
-            span,
             kind, identifier, poly_vars,
+            source: ProcedureSource::FuncUserDefined,
             return_type: None,
             parameters: Vec::new(),
             scope: ScopeId::new_invalid(),
@@ -1813,7 +1839,7 @@ pub struct CallExpression {
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Method {
-    // Builtin, accessible by programmer
+    // Builtin function, accessible by programmer
     Get,
     Put,
     Fires,
@@ -1821,10 +1847,13 @@ pub enum Method {
     Length,
     Assert,
     Print,
-    // Builtin, not accessible by programmer
+    // Builtin function, not accessible by programmer
     SelectStart, // SelectStart(total_num_cases, total_num_ports)
     SelectRegisterCasePort, // SelectRegisterCasePort(case_index, port_index, port_id)
     SelectWait, // SelectWait() -> u32
+    // Builtin component,
+    ComponentRandomU32,
+    ComponentTcpClient,
     // User-defined
     UserFunction,
     UserComponent,
@@ -1835,6 +1864,7 @@ impl Method {
         use Method::*;
         match self {
             Get | Put | Fires | Create | Length | Assert | Print => true,
+            ComponentRandomU32 | ComponentTcpClient => true,
             _ => false,
         }
     }
@@ -1866,6 +1896,7 @@ pub enum Literal {
     True,
     False,
     Character(char),
+    Bytestring(Vec<u8>),
     String(StringRef<'static>),
     Integer(LiteralInteger),
     Struct(LiteralStruct),