GLSL vec3 color preview

Question

How can I check what this will return using GLSL? vec3(20((18-0.5)2.0, 0.0), 1.0 - 2.0abs(18 - 0.5), 20((0.5-18)*2.0, 0.0)); The main goal is to create something like this VENTUSKYBILDE using the https://github.com/Rylern/InterpolateHeatmapLayer. So I apperently need to create a Vec3 function that will give me these colors in the end. I dont really have the interest in learning GLSL so I just wanna visualise the colors. How can i do this?