CURSOR/FIRST?

Sets the cursor at the first key value

Input stack: cursor

Output stack: b

If there is a first key/value pair in the database, 1 will be pushed onto the stack. Otherwise, 0 will be pushed and the cursor will be moved.

Useful in conjunction with CURSOR/CUR

PumpkinDB> ["1" "2" ASSOC COMMIT] WRITE [  CURSOR 'c SET c CURSOR/FIRST?] READ
1

Allocation

Allocates for values to be put onto the stack

Errors

NoTransaction error if there's no current write transaction

InvalidValue error if the cursor identifier is incorrect or expired

Tests

works : ["1" "2" ASSOC COMMIT] WRITE [CURSOR 'c SET c CURSOR/FIRST?] READ.
requires_txn : ["1" CURSOR/FIRST?] TRY UNWRAP 0x08 EQUAL?.
empty_stack : [CURSOR/FIRST?] TRY UNWRAP 0x04 EQUAL?.
invalid_cursor : [["1" CURSOR/FIRST?] READ] TRY UNWRAP 0x03 EQUAL?.

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