In Dire need of assistance

Hey all,

I have been fooling around with shaders (copy pasting the work of other hoping to get something working) for the latest project i'm working on but i've run in a bit of a snag.
So far I've been using Amplify/Shaderforge to built shaders but the next bit of functionality is from shader code which I very much DON'T understand.
What I guess I'm really asking is if there is some kind soul out there willing to help me convert the following bit of shader code into Amplify/Shaderforge nodes.

Code (csharp):

1. Shader "CGShader5"
2. {
3.     SubShader
4.     {
5.         Pass
6.         {
7.             /*Cull Off*/
8.  
9.             CGPROGRAM
10.  
11.             #pragma vertex vert
12.             #pragma fragment frag
13.  
14.             uniform float4x4 _CullerSpace;
15.  
16.             struct vout
17.             {
18.                 float4 pos : SV_POSITION;
19.                 float4 worldpos : TEXCOORD0;
20.                 float4 localpos : TEXCOORD1;
21.                 float4 cullerpos : TEXCOORD2;
22.             };
23.  
24.             vout vert(float4 vertex : POSITION)
25.             {
26.                 vout _out;
27.                 _out.pos = mul(UNITY_MATRIX_MVP, vertex);
28.                 _out.localpos = vertex;
29.                 _out.worldpos = mul(unity_ObjectToWorld, vertex);
30.                 _out.cullerpos = mul(_CullerSpace, _out.worldpos);
31.                 return _out;
32.             }
33.  
34.             float4 frag(vout _in) : COLOR
35.             {
36.                 /*if (length(_in.cullerpos.xyz) < 0.5)
37.                     discard;*/
38.                 if (_in.cullerpos.x > -0.5 && _in.cullerpos.x < 0.5 &&
39.                 _in.cullerpos.y > -0.5 && _in.cullerpos.y < 0.5 &&
40.                     _in.cullerpos.z > -0.5 && _in.cullerpos.z < 0.5)
41.                     discard;
42.  
43.                 return float4(0, 1, 0, 1);
44.             }
45.  
46.             ENDCG
47.         }
48.     }
49. }

p.s. all credit for the above shader goes to vexe