The affix laṭ (Present Tense) is optionally used with the force of futurity after that root, which is in a conditional sentence, is the condition precedent for the action indicated by another verb having the sense of the imperative mood.,
The word लोडर्थ means 'having the sense of the affix लोट् or imperative mood'. The force of lot is 'to command, direct, invite &c' as given in 3.3.162 and 3.3.163. The sutra, translated literally, will mean 'the present tense may optionally be employed when the action denoted by the verb is related to another action denoted by another verb in the imperative, as a sign (लक्षण) is to the thing signified (लक्ष्य)'. Thus उपाध्यायश्चेदागच्छति (आगमिष्यति or आगन्ता) अथ त्वं छन्दोऽधीष्व 'if the professor comes (i.e. will come) then read you prosody'. Here the coming of the professor is the lakshana of the direction as to reading.,