Task: Question Generation
Input (English): Passage: See also: FP (Catalogue of compositions), List of compositionsPoulenc's music is essentially diatonic. In Henri Hell's view, this is because the main feature of Poulenc's musical art is his melodic gift. In the words of Roger Nichols in the Grove dictionary, "For [Poulenc] the most important element of all was melody and he found his way to a vast treasury of undiscovered tunes within an area that had, according to the most up-to-date musical maps, been surveyed, worked and exhausted." The commentator George Keck writes, "His melodies are simple, pleasing, easily remembered, and most often emotionally expressive."Poulenc said that he was not inventive in his harmonic language. The composer Lennox Berkeley wrote of him, "All through his life, he was content to use conventional harmony, but his use of it was so individual, so immediately recognizable as his own, that it gave his music freshness and validity."  Keck considers Poulenc's harmonic language "as beautiful, interesting and personal as his melodic writing ... clear, simple harmonies moving in obviously defined tonal areas with chromaticism that is rarely more than passing". Poulenc had no time for musical theories; in one of his many radio interviews he called for "a truce to composing by theory, doctrine, rule!" He was dismissive of what he saw as the dogmatism of latter-day adherents to dodecaphony, led by René Leibowitz, and greatly regretted that the adoption of a theoretical approach had affected the music of Olivier Messiaen, of whom he had earlier had high hopes. To Hell, almost all Poulenc's music is "directly or indirectly inspired by the purely melodic associations of the human voice". Poulenc was a painstaking craftsman, though a myth grew up – "la légende de facilité" – that his music came easily to him; he commented, "The myth is excusable, since I do everything to conceal my efforts."The pianist Pascal Rogé commented in 1999 that both sides of Poulenc's musical nature were equally important: "You must accept him as a whole. If you take away either part, the serious or the non-serious, you destroy him. If one part is erased you get only a pale photocopy of what he really is." Poulenc recognised the dichotomy, but in all his works he wanted music that was "healthy, clear and robust – music as frankly French as Stravinsky's is Slav".
Output (English): What is the name of the person who greatly regretted that the adoption of a theoretical approach had affected the music of Olivier Messiaen, of whom he had earlier had high hopes?