Not at all. Using APL to solve real programming problems does lead you to cut concept space at different joints than mainstream programming, but once you have t

Not at all. Using APL to solve real programming problems does lead you to cut concept space at different joints than mainstream programming, but once you have those concepts cached, APL isn't really "dense" so much as liberatingly direct. Instead of having a function "deleteNestedNodes" you just have "d t/⍨←(t=0)⍲d≥1" or some such, which 1) is actually visually shorter, 2) immediately gives you handles for modifying as needed, and 3) tells you algorithmic complexity on its face. That said, large corporate APL systems also use lots of standard architectural concepts like OOP, control structure flow, etc. and tend to have overall much less code density than you might expect, and the lines tend to be wicked short on average. So 425,000 lines isn't really "pages and pages of dense APL" in practice.