NGN/APL

NGN/APL allows redefining primitives, so redefining all primitive functions to ⊢ ("pass through": both ⊢3 and 2⊢3 gives 3) makes the language completely useless:

⍪←⊢⋄-←⊢⋄+←⊢⋄?←⊢⋄⍵←⊢⋄∊←⊢⋄⍴←⊢⋄~←⊢⋄↑←⊢⋄↓←⊢⋄⍳←⊢⋄○←⊢⋄*←⊢⋄⌈←⊢⋄⌊←⊢⋄⍕←⊢⋄⊂←⊢⋄⊃←⊢⋄∩←⊢⋄∪←⊢⋄⊥←⊢⋄⊤←⊢⋄|←⊢⋄<←⊢⋄≤←⊢⋄=←⊢⋄≥←⊢⋄>←⊢⋄≠←⊢⋄∨←⊢⋄∧←⊢⋄×←⊢⋄÷←⊢⋄⍒←⊢⋄⍋←⊢⋄⌽←⊢⋄⍉←⊢⋄⊖←⊢⋄⍟←⊢⋄⍱←⊢⋄⍲←⊢⋄!←⊢⋄⌹←⊢⋄⊣←⊢⋄⍎←⊢

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NGN/APL

NGN/APL allows redefining primitives, so redefining (←) all primitive functions to ⊢ ("pass through": both ⊢3 and 2⊢3 gives 3) makes the language completely useless:

⍪←-←+←?←⍵←∊←⍴←~←↑←↓←⍳←○←*←⌈←⌊←⍕←⊂←⊃←∩←∪←⊥←⊤←|←<←≤←=←≥←>←≠←∨←∧←×←÷←⍒←⍋←⌽←⍉←⊖←⍟←⍱←⍲←!←⌹←⊣←⍎←⊢

Try it here.

NGN/APL

NGN/APL allows redefining primitives, so +←= removes the ability to add two numbers. Try it here.

NGN/APL

NGN/APL allows redefining primitives, so redefining all primitive functions to ⊢ ("pass through": both ⊢3 and 2⊢3 gives 3) makes the language completely useless:

⍪←⊢⋄-←⊢⋄+←⊢⋄?←⊢⋄⍵←⊢⋄∊←⊢⋄⍴←⊢⋄~←⊢⋄↑←⊢⋄↓←⊢⋄⍳←⊢⋄○←⊢⋄*←⊢⋄⌈←⊢⋄⌊←⊢⋄⍕←⊢⋄⊂←⊢⋄⊃←⊢⋄∩←⊢⋄∪←⊢⋄⊥←⊢⋄⊤←⊢⋄|←⊢⋄<←⊢⋄≤←⊢⋄=←⊢⋄≥←⊢⋄>←⊢⋄≠←⊢⋄∨←⊢⋄∧←⊢⋄×←⊢⋄÷←⊢⋄⍒←⊢⋄⍋←⊢⋄⌽←⊢⋄⍉←⊢⋄⊖←⊢⋄⍟←⊢⋄⍱←⊢⋄⍲←⊢⋄!←⊢⋄⌹←⊢⋄⊣←⊢⋄⍎←⊢

Try it here.