Question

I am parsing string records in this form:

description: double/double/double

for ex.:

item description: 0.4/8/-24.66

Each record should result in an object:

new MyObj("first item", 0.4, 2.4, -24.66)

I could easily do this with a regular expression and a procedural approach, but the resulting code is error-prone and rather ugly (at least from a functional point of view).

How can this be accomplished in a more elegant way?

Answer 1

Or you can just create a simple parser function string->MyObj like this:

type MyObj(descr:string, a:float, b:float, c:float) =
    override this.ToString() =
        System.String.Format("{0}: {1}; {2}; {3}", descr,a,b,c)

let myobjfromstr (str:string) = 
    let flds = str.Split([|':';'/'|])
    let ip s = System.Double.Parse(s)    
    new MyObj(flds.[0], ip flds.[1], ip flds.[2], ip flds.[3])

myobjfromstr "item description: 0.4/8/-24.66" |> printfn "%A"

(update: I guessed that records were separated by a new-line or something like that and were split into a list. On the second thought, there’s nothing like that in your question…)