FWP:
Ghalib has done an elegant thing with sanj and ((ar.z , by exploiting the wide range of their meanings (see the definitions above). The lover adjures himself to cut to the chase, to describe the essence of his situation. He then depicts himself as either a strange kind of surveyor (a 'longing-measurer' of 'breadths') or a strange kind of expert judge (a 'longing-examiner' of 'petitions'). In other words, even when the lover urges himself to make a brief, pithy [mu;xta.sar] abstract or statement of his situation, the result remains elusive. The lover wraps up his whole life within a single claim to a terrible kind of expertise: he's a professional assessor of suffering.
The objection that Nazm makes is that sanj is traditionally used with words evoking music or sound (as can be seen from Platts's examples too). Thus it can easily be used for a 'measurer' of the pace of music, or the metrical rhythm of poetry. But here it has been applied by extension to 'sorrow, longing, desire', which have no musical flow or poetic meter (unless the poet 'writes them in'). Nazm disapproves, but how much do we care? It's like criticizing Shakespeare for his neologisms.
Nazm:
In Persian sanjiidan means 'to weigh' and 'to make measured/harmonious'. Thus navaa-sanj , na;Gmah-sanj , zamzamah-sanj , taraanah-sanj , nuktah-sanj are all familiar constructions and are on the lips of correct speakers. But later connoisseurs of the language and their followers, like Bedil, etc., have begun to formally versify aarzuu-sanj , ;hasrat-sanj , shikvah-sanj as well, and this is not free of artificiality [ta.sannu((].
== Nazm page 26