No suffix implies the "seconds" unit:
>>> parseOnly diffTime "10"
Right 10s
Various units (seconds, minutes, hours, days):
>>> parseOnly diffTime "10s"
Right 10s
>>> parseOnly diffTime "10m"
Right 600s
>>> parseOnly diffTime "10h"
Right 36000s
>>> parseOnly diffTime "10d"
Right 864000s
Metric prefixes to seconds (down to Pico):
>>> parseOnly diffTime "10ms"
Right 0.01s
>>> parseOnly diffTime "10μs"
Right 0.00001s
>>> parseOnly diffTime "10us"
Right 0.00001s
>>> parseOnly diffTime "10ns"
Right 0.00000001s
>>> parseOnly diffTime "10ps"
Right 0.00000000001s
Negative values:
>>> parseOnly diffTime "-1s"
Right -1s
Unsupported units:
>>> parseOnly diffTime "1k"
Left "diffTime: Failed reading: Unsupported unit: \"k\""