diff --git a/src/codegen_x86_64.rs b/src/codegen_x86_64.rs
index 4369d88..704daee 100644
--- a/src/codegen_x86_64.rs
+++ b/src/codegen_x86_64.rs
@@ -125,37 +125,37 @@ extern closedir
 extern exit
 extern gettimeofday
 
-section .text.deref
-deref:
+section .text._builtin_deref
+_builtin_deref:
     mov rax, qword [rdi]
     ret
 
-section .text.IO.stdin
-IO.stdin:
+section .text._builtin_stdin
+_builtin_stdin:
     mov rax, [rel stdin]
     ret
 
-section .text.Bit.lshift
-Bit.lshift:
+section .text._builtin_lshift
+_builtin_lshift:
     mov rcx, rsi
     mov rax, rdi
     shl rax, cl
     ret
 
-section .text.Bit.rshift
-Bit.rshift:
+section .text._builtin_rshift
+_builtin_rshift:
     mov rcx, rsi
     mov rax, rdi
     sar rax, cl
     ret
 
-section .text.String.set
-String.set:
+section .text._builtin_string_set
+_builtin_string_set:
     mov [rdi + rsi], dl
     ret
 
-section .text.OS.listdir
-OS.listdir:
+section .text._builtin_listdir
+_builtin_listdir:
     push r14
     push rbx
     push rax
@@ -165,29 +165,29 @@ OS.listdir:
     mov rdi, r14
     call opendir
     mov r14, rax
-.OS.listdir.1:
+._builtin_listdir.1:
     mov rdi, r14
     call readdir
     test rax, rax
-    je .OS.listdir.3
+    je ._builtin_listdir.3
     cmp byte [rax+19], 46
-    jne .OS.listdir.2
+    jne ._builtin_listdir.2
     movzx ecx, byte [rax+20]
     test ecx, ecx
-    je .OS.listdir.1
+    je ._builtin_listdir.1
     cmp ecx, 46
-    jne .OS.listdir.2
+    jne ._builtin_listdir.2
     cmp byte [rax+21], 0
-    je .OS.listdir.1
-.OS.listdir.2:
+    je ._builtin_listdir.1
+._builtin_listdir.2:
     add rax, 19
     mov rdi, rax
     call strdup
     mov rsi, rax
     mov rdi, rbx
     call Array.push
-    jmp .OS.listdir.1
-.OS.listdir.3:
+    jmp ._builtin_listdir.1
+._builtin_listdir.3:
     mov rdi, r14
     call closedir
     mov rax, rbx
@@ -196,14 +196,14 @@ OS.listdir:
     pop r14
     ret
 
-section .text.Array.set
-Array.set:
+section .text._builtin_array_set
+_builtin_array_set:
     mov rax, [rdi]
     mov [rax + rsi*8], rdx
     ret
 
-section .text.Array.push
-Array.push:
+section .text._builtin_array_push
+_builtin_array_push:
     push r14
     push rbx
     push rax
@@ -212,7 +212,7 @@ Array.push:
     mov rax, [rdi]
     mov rcx, [rdi + 16]
     cmp rcx, [rdi + 8]
-    jne .Array.push.1
+    jne ._builtin_array_push.1
     lea rdx, [rcx + rcx]
     mov rsi, 4
     test rcx, rcx
@@ -223,7 +223,7 @@ Array.push:
     call realloc
     mov [rbx], rax
     mov rcx, [rbx + 16]
-.Array.push.1:
+._builtin_array_push.1:
     mov [rax + rcx*8], r14
     inc qword [rbx + 16]
     add rsp, 8
@@ -231,13 +231,13 @@ Array.push:
     pop r14
     ret
 
-section .text.Array.size
-Array.size:
+section .text._builtin_array_size
+_builtin_array_size:
     mov rax, [rdi + 16]
     ret
 
-section .text.Array.free
-Array.free:
+section .text._builtin_array_free
+_builtin_array_free:
     push rbx
     mov rbx, rdi
     mov rdi, [rdi]
diff --git a/src/std.zr b/src/std.zr
index 3f877c6..df3db50 100644
--- a/src/std.zr
+++ b/src/std.zr
@@ -9,7 +9,10 @@ func print_i64[x: I64] : I64
     printf("%ld\n", x)
 
 func String.nth[s: String, n: I64] : U8
-    return deref(s + n)
+    return _builtin_deref(s + n)
+
+func String.set[s: String, n: I64] : I64
+    _builtin_string_set(s, n)
 
 func String.is_whitespace[c: U8] : Bool
     return c == ' ' || c == 10 || c == 13 || c == 9
@@ -20,10 +23,10 @@ func String.concat[a: String, b: String] : String
     strcat(c, b)
     return c
 
-func String.find[s: String, needle: U8] : I64
+func String.find[s: String, c: U8] : I64
     let s_len: I64 = strlen(s)
     for i in 0..s_len
-        if String.nth(s, i) == needle
+        if String.nth(s, i) == c
             return i
     return -1
 
@@ -57,6 +60,9 @@ func String.rev[s: String] : String
     String.set(out, len, 0)
     return out
 
+func IO.stdin[]: Ptr
+    return _builtin_stdin()
+
 func IO.read_line[]: String
     let buffer: String = malloc(1024)
     fgets(buffer, 1024, IO.stdin())
@@ -163,21 +169,39 @@ func Math.urandom[]: I64
     let file: Ptr = fopen("/dev/urandom", "rb")
     fread(buffer, 8, 1, file)
     fclose(file)
-    let n: I64 = deref(buffer)
+    let n: I64 = _builtin_deref(buffer)
     free(buffer)
     return n
 
 func Array.new[] : Array
     return calloc(1, 24)
 
+func Array.set[xs: Array, n: I64, x: I64] : I64
+    _builtin_array_set(xs, n, x)
+
+func Array.push[xs: Array, x: I64] : I64
+    return _builtin_array_push(xs, x)
+
+func Array.size[xs: Array] : I64
+    return _builtin_array_size(xs)
+
 func OS.time[] : I64
     let tv: Ptr = malloc(16)
     gettimeofday(tv, 0)
-    let seconds: I64 = deref(tv)
-    let microseconds: I64 = deref(tv+8)
+    let seconds: I64 = _builtin_deref(tv)
+    let microseconds: I64 = _builtin_deref(tv+8)
     free(tv)
     return seconds * 1000 + microseconds / 1000
 
+func OS.listdir[path: String] : Array
+    return _builtin_listdir(path)
+
+func Bit.lshift[a: I64, b: I64] : I64
+    return _builtin_lshift(a, b)
+
+func Bit.rshift[a: I64, b: I64] : I64
+    return _builtin_rshift(a, b)
+
 func Crypto.hex_encode[s: String] : String
     let hex_chars: String = "0123456789abcdef"
     let s_len: I64 = strlen(s)
@@ -227,7 +251,7 @@ func Crypto.rc4[key: String, plaintext: String]: String
         let tmp: U8 = String.nth(S, i)
         String.set(S, i, String.nth(S, j))
         String.set(S, j, tmp)
-        
+
     let i: I64 = 0
     j = 0
     let plaintext_len: I64 = strlen(plaintext)