Functional unparsing

[Andrey Riabushenko <cdome@bk.ru>]

Hi ocaml developers,

I am currently developing a library for multivariate regressions including 
linear, nonlinear, generalized, weighted and so on. In my opinion most the 
convenient interface is the one described further and is based on functional 
unparsing.

Something like that:

Stats.linear_regression "y ~ x1 exp(x2) log(x3) x3^2" 
Returns float -> float -> float -> float -> regression_result = <fun>

Stats.generalized_regression "log(y) ~ x1 x^2 log(x3) " 
Returns float -> float -> float -> float -> regression_result = <fun>

For time series:
Stats.ts_regression "y ~ ARMA(5,3)"
Stats.ts_regression "y ~ ARMA(2,2) GARCH(2,1)"


If want to ask you two questions. 
1. Do you find such interface convenient? Critique is welcome. If you have 
better idea, please tell me. I will make all publicly available.

2. The second question regarding function unparsing. I haven't used this 
technique before. Are there some docs, blog articles, descriptions and etc? 
The only relevant documentation I have found is printf.ml :). Might someone 
have a minimal working example to demonstrate?