5.4.87
अहस्सर्वैकदेशसंख्यातपुण्याच्च रात्रेः
Operational rule vidhi
The affix अच् comes after the word रात्रि when preceded by अहन् or सर्व or a word denoting a portion of night, or संख्यात or पुण्य when the compound is a तत्-पुरुष as well as when a numeral or an indeclinable precedes रात्रि.
Word by word (padaccheda)
Left context अहः- सर्व- एकदेश- सङ्ख्यात- पुण्यात् pañcamī · ekavacanaIndeclinable च avyayaLeft context रात्रेः pañcamī · ekavacana
- Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.
- Indeclinable An avyaya such as च "and", वा "optionally", न "not".
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Full reading
अहः-
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
The affix अच् comes after the word रात्रि when preceded by अहन् or सर्व or a word denoting a portion of night, or संख्यात or पुण्य when the compound is a तत्-पुरुष as well as when a numeral or an indeclinable precedes रात्रि।
The anuvritti of संख्याव्ययादेः is drawn in to this sutra by force of the word च् "and" of the sutra. The word अहन् forms a Dvandva compound as अहश्च रात्रिश्च = अहोरात्रः "day and night". So also सर्वरात्रः, पूर्वरात्रः 'the first part of night' : अपररात्रः 'the latter part of night'. These are formed by 2.2.1. So also संख्याता रात्रिः = संख्यातरात्रः ॥ This compound is formed by 2.1.57. So also पुण्या रात्रिः = पुण्यरात्रः । So also when compounded with a Numeral or an Indeclinable : as, द्वे रात्री समाहृते = द्विरात्रः, त्रिरात्रः, अतिक्रान्तो रात्रिम् = अतिरात्रः, नोरात्रः ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.