Method PreparseIfElse

Source/script.cpp:4977–5266

Line *Script::PreparseIfElse(Line *aStartingLine, ExecUntilMode aMode, AttributeType aLoopTypeFile
	, AttributeType aLoopTypeReg, AttributeType aLoopTypeRead, AttributeType aLoopTypeParse)
// Zero is the default for aMode, otherwise:
// Will return NULL to the top-level caller if there's an error, or if
// mLastLine is NULL (i.e. the script is empty).
// Note: This function should be called with aMode == ONLY_ONE_LINE
// only when aStartingLine's ActionType is something recursable such
// as IF and BEGIN_BLOCK.  Otherwise, it won't return after only one line.
{
	// Don't check aStartingLine here at top: only do it at the bottom
	// for it's differing return values.
	Line *line_temp;
	// Although rare, a statement can be enclosed in more than one type of special loop,
	// e.g. both a file-loop and a reg-loop:
	AttributeType loop_type_file, loop_type_reg, loop_type_read, loop_type_parse;
	for (Line *line = aStartingLine; line != NULL;)
	{
		if (ACT_IS_IF(line->mActionType) || line->mActionType == ACT_LOOP || line->mActionType == ACT_REPEAT)
		{
			// ActionType is an IF or a LOOP.
			line_temp = line->mNextLine;  // line_temp is now this IF's or LOOP's action-line.
			if (line_temp == NULL) // This is an orphan IF/LOOP (has no action-line) at the end of the script.
				// Update: this is now impossible because all scripts end in ACT_EXIT.
				return line->PreparseError("This if-statement or loop has no action.");
			if (line_temp->mActionType == ACT_ELSE || line_temp->mActionType == ACT_BLOCK_END)
				return line->PreparseError("The line beneath this IF or LOOP is an invalid action.");

			// We're checking for ATTR_LOOP_FILE here to detect whether qualified commands enclosed
			// in a true file loop are allowed to omit their filename paremeter:
			loop_type_file = ATTR_NONE;
			if (aLoopTypeFile == ATTR_LOOP_FILE || line->mAttribute == ATTR_LOOP_FILE)
				// i.e. if either one is a file-loop, that's enough to establish
				// the fact that we're in a file loop.
				loop_type_file = ATTR_LOOP_FILE;
			else if (aLoopTypeFile == ATTR_LOOP_UNKNOWN || line->mAttribute == ATTR_LOOP_UNKNOWN)
				// ATTR_LOOP_UNKNOWN takes precedence over ATTR_LOOP_NORMAL because
				// we can't be sure if we're in a file loop, but it's correct to
				// assume that we are (otherwise, unwarranted syntax errors may be reported
				// later on in here).
				loop_type_file = ATTR_LOOP_UNKNOWN;
			else if (aLoopTypeFile == ATTR_LOOP_NORMAL || line->mAttribute == ATTR_LOOP_NORMAL)
				loop_type_file = ATTR_LOOP_NORMAL;

			// The section is the same as above except for registry vs. file loops:
			loop_type_reg = ATTR_NONE;
			if (aLoopTypeReg == ATTR_LOOP_REG || line->mAttribute == ATTR_LOOP_REG)
				loop_type_reg = ATTR_LOOP_REG;
			else if (aLoopTypeReg == ATTR_LOOP_UNKNOWN || line->mAttribute == ATTR_LOOP_UNKNOWN)
				loop_type_reg = ATTR_LOOP_UNKNOWN;
			else if (aLoopTypeReg == ATTR_LOOP_NORMAL || line->mAttribute == ATTR_LOOP_NORMAL)
				loop_type_reg = ATTR_LOOP_NORMAL;

			// Same as above except for READ-FILE loops:
			loop_type_read = ATTR_NONE;
			if (aLoopTypeRead == ATTR_LOOP_READ_FILE || line->mAttribute == ATTR_LOOP_READ_FILE)
				loop_type_read = ATTR_LOOP_READ_FILE;
			else if (aLoopTypeRead == ATTR_LOOP_UNKNOWN || line->mAttribute == ATTR_LOOP_UNKNOWN)
				loop_type_read = ATTR_LOOP_UNKNOWN;