diff --git a/src/ast_builder.rs b/src/ast_builder.rs
index 098fb85..7ff4854 100644
--- a/src/ast_builder.rs
+++ b/src/ast_builder.rs
@@ -1,3 +1,8 @@
+mod random_generators;
+
+use random_generators::IntGenerator;
+use random_generators::FloatGenerator;
+
 use rand::Rng;
 use rand::seq::SliceRandom;
 use rand_distr::Distribution;
@@ -58,6 +63,8 @@ impl AstBuilder {
             } else if a_lt(&mut p, self.params.global_flow.gen_typedef) {
                 let typedef = self.gen_typedef();
                 self.ast.push(typedef);
+            } else if a_lt(&mut p, self.params.global_flow.gen_subroutine) {
+                panic!("Subroutines aren't ready yet");
             } else {
                 let decl = self.gen_global_decl();
                 self.ast.push(decl);
@@ -222,69 +229,3 @@ impl ToString for AstBuilder {
         s
     }
 }
-
-/// Generates values from regions of interest for an integer
-///
-/// These are concentrated around i32::MIN, 0, and i32::MAX, though any i32 value is possible
-struct IntGenerator {
-    distro_pos: rand_distr::Normal<f32>,
-    distro_zero: rand_distr::Normal<f32>,
-    distro_neg: rand_distr::Normal<f32>,
-}
-
-impl IntGenerator {
-    fn new(p: &Params) -> Self {
-        Self {
-            distro_pos: rand_distr::Normal::new(0.0, p.dev.int_gen_distro_pos_stddiv).unwrap(),
-            distro_zero: rand_distr::Normal::new(0.0, 3.0).unwrap(),
-            distro_neg: rand_distr::Normal::new(0.0, p.dev.int_gen_distro_neg_stddiv).unwrap(),
-        }
-    }
-}
-
-impl Distribution<i32> for IntGenerator {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i32 {
-        let p: f64 = rng.gen();
-
-        if p < 0.3 {
-            i32::MAX - (self.distro_pos.sample(rng).abs() as i32)
-        } else if p < 0.7 {
-            self.distro_zero.sample(rng) as i32
-        } else {
-            -1 * (i32::MAX - (self.distro_pos.sample(rng).abs() as i32))
-        }
-    }
-}
-
-/// Generates values from regions of interest for a float
-///
-/// These are concentrated around f32::MIN, 0, and f32::MAX, though any f32 value is possible
-struct FloatGenerator {
-    distro_pos: rand_distr::Normal<f32>,
-    distro_zero: rand_distr::Normal<f32>,
-    distro_neg: rand_distr::Normal<f32>,
-}
-
-impl FloatGenerator {
-    fn new(p: &Params) -> Self {
-        Self {
-            distro_pos: rand_distr::Normal::new(1.0, p.dev.float_gen_distro_pos_stddiv).unwrap(),
-            distro_zero: rand_distr::Normal::new(0.0, 3.0).unwrap(),
-            distro_neg: rand_distr::Normal::new(1.0, p.dev.float_gen_distro_neg_stddiv).unwrap(),
-        }
-    }
-}
-
-impl Distribution<f32> for FloatGenerator {
-    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f32 {
-        let p: f64 = rng.gen();
-
-        if p < 0.33 {
-            f32::MAX - self.distro_pos.sample(rng).abs()
-        } else if p < 0.66 {
-            self.distro_zero.sample(rng)
-        } else {
-            -1.0 * (f32::MAX - self.distro_neg.sample(rng).abs())
-        }
-    }
-}
diff --git a/src/ast_builder/random_generators.rs b/src/ast_builder/random_generators.rs
new file mode 100644
index 0000000..73d1c60
--- /dev/null
+++ b/src/ast_builder/random_generators.rs
@@ -0,0 +1,67 @@
+use super::*;
+
+/// Generates values from regions of interest for an integer
+///
+/// These are concentrated around i32::MIN, 0, and i32::MAX, though any i32 value is possible
+pub struct IntGenerator {
+    distro_pos: rand_distr::Normal<f32>,
+    distro_zero: rand_distr::Normal<f32>,
+    distro_neg: rand_distr::Normal<f32>,
+}
+
+impl IntGenerator {
+    pub fn new(p: &Params) -> Self {
+        Self {
+            distro_pos: rand_distr::Normal::new(0.0, p.dev.int_gen_distro_pos_stddiv).unwrap(),
+            distro_zero: rand_distr::Normal::new(0.0, 3.0).unwrap(),
+            distro_neg: rand_distr::Normal::new(0.0, p.dev.int_gen_distro_neg_stddiv).unwrap(),
+        }
+    }
+}
+
+impl Distribution<i32> for IntGenerator {
+    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i32 {
+        let p: f64 = rng.gen();
+
+        if p < 0.3 {
+            i32::MAX - (self.distro_pos.sample(rng).abs() as i32)
+        } else if p < 0.7 {
+            self.distro_zero.sample(rng) as i32
+        } else {
+            -1 * (i32::MAX - (self.distro_pos.sample(rng).abs() as i32))
+        }
+    }
+}
+
+/// Generates values from regions of interest for a float
+///
+/// These are concentrated around f32::MIN, 0, and f32::MAX, though any f32 value is possible
+pub struct FloatGenerator {
+    distro_pos: rand_distr::Normal<f32>,
+    distro_zero: rand_distr::Normal<f32>,
+    distro_neg: rand_distr::Normal<f32>,
+}
+
+impl FloatGenerator {
+    pub fn new(p: &Params) -> Self {
+        Self {
+            distro_pos: rand_distr::Normal::new(1.0, p.dev.float_gen_distro_pos_stddiv).unwrap(),
+            distro_zero: rand_distr::Normal::new(0.0, 3.0).unwrap(),
+            distro_neg: rand_distr::Normal::new(1.0, p.dev.float_gen_distro_neg_stddiv).unwrap(),
+        }
+    }
+}
+
+impl Distribution<f32> for FloatGenerator {
+    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> f32 {
+        let p: f64 = rng.gen();
+
+        if p < 0.33 {
+            f32::MAX - self.distro_pos.sample(rng).abs()
+        } else if p < 0.66 {
+            self.distro_zero.sample(rng)
+        } else {
+            -1.0 * (f32::MAX - self.distro_neg.sample(rng).abs())
+        }
+    }
+}