Function patch_seq_call 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn patch_seq_call(stack: Stack) -> Stack

Call a quotation or closure

Pops a quotation or closure from the stack and executes it. For stateless quotations, calls the function with just the stack. For closures, calls the function with both the stack and captured environment. The function takes the current stack and returns a new stack.

Stack effect: ( ..a quot – ..b ) where the quotation has effect ( ..a – ..b )

TCO Considerations

With Arc-based closure environments, this function is tail-position friendly: no cleanup is needed after the call returns (Arc ref-counting handles it).

However, full musttail TCO across quotations and closures is limited by calling convention mismatches:

• Quotations use tailcc with signature: fn(Stack) -> Stack
• Closures use C convention with signature: fn(Stack, *const Value, usize) -> Stack

LLVM’s musttail requires matching signatures, so the compiler can only guarantee TCO within the same category (quotation-to-quotation or closure-to-closure). Cross-category calls go through this function, which is still efficient but doesn’t use musttail.

Safety

• Stack must not be null
• Top of stack must be a Quotation or Closure value
• Function pointer must be valid
• Quotation signature: Stack -> Stack
• Closure signature: Stack, *const Value -> Stack