1. A computer-implemented process for producing a desired output item from one or more input items employing a probabilistic program generated using input-output examples, comprising: using a computer to perform the following process actions: receiving input-output examples, each input-output example providing one or more input items and a corresponding desired output item; parsing the input items and the output items to produce a weighted set of parses, each weighted parse representing a different potential parsing of each input and output item weighted in accordance with a measure of the likelihood the parsing is a valid parsing based on a comparison to a library of parses; for each input-output example, identifying one or more transforms from a library of transforms of a type that can produce the desired output item from the input items, and identifying formatting instructions which are capable of formatting an output item so as to match the formatting of the desired output item of the input-output example; generating a probabilistic program which given one or more input items of the same type as the input items of the input-output examples, employs the identified transforms and the formatting instructions, to produce an output item corresponding to the one or more input items; and receiving one or more input items of the same type as the input items of the input-output examples, and producing an output item corresponding to the received input item using the generated probabilistic program.