I searched the tex.stackexchange archives for an answer to this question but couldn't find one. I assume it's a common question, however.
I often want to align text similar to the poly environment in lhs2TeX. For instance:
e(x) = x e(M N) = e(M) e(N) e(λx:τ.M) = λx:τ.e(M) e(λ_:τ.M) = λx:τ.e(M) (x ∉ FV(M))
The solutions I see are to use a tabular environment, an eqnarray, or an align. However, align and eqnarray create columns that are too far apart, and tabular has similar, but less significant spacing problems.
Is there a simple solution to this problem? The layout is common, so I assume there is.