### Compilation failed:

error: 1: 'main' must return: 'vec4', 'float4', or 'half4'
uniform float a; int b; void main() { sk_FragColor.x = half(ldexp(a, b)); }
                        ^^^^^^^^^^^
error: 1: unknown identifier 'sk_FragColor'
uniform float a; int b; void main() { sk_FragColor.x = half(ldexp(a, b)); }
                                      ^^^^^^^^^^^^
error: 1: unknown identifier 'ldexp'
uniform float a; int b; void main() { sk_FragColor.x = half(ldexp(a, b)); }
                                                            ^^^^^
3 errors