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Add functions - #128
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Add functions#128
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PUSH_SADDR pushes the lvalue pointer to the 6502 stack. POP_SADDR restores it while preserving A and X, so a function result in AX survives. Y is clobbered but next_instruction reloads it from sptr. Aided by Opencode / DeepSeek V4.1 Flash 1017
Add RETURN expr for procedures, returning an integer value in AX. RETURN inside an active FOR loop is supported by emitting one TOK_FOR_EXIT per loop before TOK_RET, so the AX result survives. The native parser uses a single bad RETURN error for invalid returns; the cross compiler keeps explanatory outside-PROC messages. Add tests for returns inside nested FOR loops and repeated function calls. Aided by Opencode / DeepSeek V4.1 Flash 1017
Add @name(args) to integer expressions. Calls use PUSH_SADDR/POP_SADDR around argument evaluation so array and memory destinations survive the call; the cross compiler removes unnecessary pairs. TOK_RET now preserves A because the function result is in AX. The native parser shares its variable stack for saved labels and inlines the one-use FUNC_ARGS rule. Function argument counts use the empty FUNC_ARG_OK hook implemented by E_COUNT_PARAM in the cross compiler. Add tests for calls, nested calls, recursion, parser stack use, and SADDR preservation in byte and word array assignments. Aided by Opencode / DeepSeek V4.1 Flash 1017
Add a cross-compiler peephole pass that tracks pending SADDR lvalue addresses and removes PUSH_SADDR/POP_SADDR pairs around calls when no address is live. It handles POKE, DPOKE, NUM_POKE, BYTE_POKE, FP_STORE, COPY_STR, INC and DEC as consumers, and drops nested saves inside an already-saved region. Keep the native parser unchanged and always emitting the wrappers. Add tests for function calls in POKE/DPOKE address and value expressions, including functions whose bodies clobber SADDR. Aided by Opencode / DeepSeek V4.1 Flash 1017
Return success booleans from InputLine and InputFilename, and rename AskSaveFileChanged to CheckUnsavedChanges with a positive "may continue" result. This removes the old KEY-variable convention from the callers while keeping the IDE the same size. Aided by Opencode / DeepSeek V4.1 Flash 1017
Use the existing conditional return-of-zero tokens when a conditional branch contains only RETURN 0. This removes the jump, constant load and RET while preserving the preceding COMP_0, so full 16-bit non-zero function results are handled correctly. Add a test covering zero, odd, even and 16-bit non-zero values in both branch directions; declare the test variable with DIM before use. Aided by Opencode / DeepSeek V4.1 Flash 1017
Mark labels called with @name(...) as functions and flag any RETURN inside the current PROC. At the end of the cross-compiler parse, report an error if a function was used in an expression but never contains a RETURN. This deliberately checks only for at least one RETURN, not full control-flow coverage, matching the language's permissive behavior. Add cross-only error coverage and a test that conditional-only returns are accepted. Native compiler behavior is unchanged. Aided by Opencode / DeepSeek V4.1 Flash 1017
Make the RETURN expression optional. A bare RETURN exits the current PROC, unwinding active FOR state, without producing a value. This is useful for early exits from nested loops. Only value-returning RETURN statements mark a function for the cross-compiler diagnostic; a bare RETURN does not count. FBI.XEX grows from 8299 to 8304 bytes. Aided by Opencode / DeepSeek V4.1 Flash 1017
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Add functions to FastBasic.
This PR adds a RETURN statement that can return values from a PROC, and a @ syntax that allows calling the functions from any expression.
Fixes #69 and #109.