first commit

pigo/internal/runtime/args.go

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+// This file implements shell-style argument tokenization for prompt templates
+// (US-001, #331). A template invocation like
+//
+//	/component Button "click handler"
+//
+// arrives at the expander as the raw string `Button "click handler"`; the
+// expander needs positional args ($1, $@, ...), so the string must be split into
+// ["Button", "click handler"] honoring shell quoting rules: double and single
+// quotes group a single argument, surrounding quotes are stripped, and internal
+// whitespace is preserved.
+//
+// Rather than hand-roll a tokenizer, we reuse a mature shell-quoting library
+// (github.com/kballard/go-shellquote), per the project's "reuse rather than reinvent" rule.
+package runtime
+
+import "github.com/kballard/go-shellquote"
+
+// SplitArgs tokenizes a raw argument string using shell-style quoting rules.
+// Double quotes ("a b") and single quotes ('a b') each group one argument;
+// surrounding quotes are stripped and internal whitespace is preserved. An empty
+// (or all-whitespace) input yields an empty non-nil slice with no error. An
+// unterminated quote yields an error, so the caller can fall back to treating
+// the whole string as $ARGUMENTS rather than feeding a malformed arg list to the
+// template engine.
+func SplitArgs(s string) ([]string, error) {
+	parts, err := shellquote.Split(s)
+	if err != nil {
+		return nil, err
+	}
+	if parts == nil {
+		return []string{}, nil
+	}
+	return parts, nil
+}