2G. Verb Trains

The following phrases illustrate how trains may be substituted for other constructs, often giving expressions that are more readable, particularly to readers more familiar with expressions from mathematics:

m0=: >: @ +: @ i.

First odd integers

m1=: 1: + 2: * i.

Same as m0

m2=: +/ @ (1: + 2: * i.)

Sum of odd integers

m3=: [: +/ 1: + 2: * i.

Same as m2 using cap

m4=: m2 -: *: 

Sum of odds is square (Tautology)

m5=: < i. 1:

The first element where x<y ;  also works for = ~: < <: >: > E. 

m6=: < i. 0:

The first element where not x<y

m7=: < i: 1:

The last element where x<y

m8=: < i: 0:

The last element where not x<y

m9=: [: +/ <

The number of elements where x<y