Translator – PRINT Command (Translating)

Currently, command tokens are pushed onto the command stack, so will a PRINT command token when it is received. The PRINT's next token mode value will be set to Expression. The Semicolon, Comma and End-of-statement will trigger the insertion of the value specific print code.

The existing find code function can be used to determine which specific print value code to append to the output. The PrintDbl code will serve as the main code, which will have PrintInt, PrintStr and PrintTmpStr as associated codes, each with one operand of the appropriate data type. A new token will be created with the PrintDbl code and passed to the find code function, which will return the correct code for the expression. The token is then be appended to the output.

At the end of the statement, the PRINT command token will be on top of the command stack. The end of statement processing needs to pop this token off from the stack and perform whatever handling is necessary. There needs to be a command handler that performs a command's specific needs. For reasons that will be clear later, the token handler function cannot be used for this purpose, so a new command handler function pointer is required in the table entries.

The PRINT command handler needs to determine when the PRINT token should be appended to the output (to go to a new line), or not (stay on the same line). If the done stack is not empty, then there is an unprocessed expression that needs a specific print value code. This means there was no semicolon or comma at the end of the statement, so the PRINT token can be appended. However, an empty done stack does not indicate no PRINT token is needed, consider the PRINT command by itself.

Therefore, a flag is needed, to be set when an print-only internal function, semicolon or comma is processed. If the done stack was empty, the command handler will check if this flag is set, to determine not to append the PRINT command token (in which case the PRINT token is deleted). This flag will be added to the command stack's item structure item, which is cleared when the command is initially pushed onto the stack.