xo-reader2: support 0-argument apply-expressions

This commit is contained in:
Roland Conybeare 2026-02-28 13:21:54 +11:00
commit 6795c1bc15
7 changed files with 138 additions and 77 deletions

View file

@ -30,12 +30,13 @@ namespace xo {
* apply_0 --on_expr()--> apply_1
* apply_1 --on_leftparen()--> apply_2
* apply_2 --on_expr()--> apply_3
* --on_rightparen()--> (done)
* apply_3 --on_comma()--> apply_2
* --on_rightparen()-> (done)
* --on_rightparen()--> (done)
*
* apply_0: start
* apply_1: leftparen following expr allows parser to recognize apply
* apply_2: expect next argument
* apply_2: expect next argument, or rightparent to continue
* apply_3: got argument, expect comma or rightparen to continue
* (done): apply complete, pop exprstate from stack
*
@ -129,6 +130,15 @@ namespace xo {
void on_leftparen_token(const Token & tk,
ParserStateMachine * p_psm);
/** handle rightparen token @p tk for this ssm,
* with overall parser state in @p p_psm.
*
* Rightparen will complete apply-expression,
* terminating this syntax.
**/
void on_rightparen_token(const Token & tk,
ParserStateMachine * p_psm);
///@}
/** @defgroup ssm-applyssm-facet syntaxstatemachine facet methods **/
///@{
@ -177,9 +187,14 @@ namespace xo {
///@}
private:
/** @defgroup ssm-applyssm-mpl-methods **/
/** @defgroup ssm-applyssm-impl-methods **/
///@{
/** create final apply-expression for this syntax,
* using @p mm for memory
**/
obj<AExpression> assemble_expr(obj<AAllocator> mm);
///@}
private:

View file

@ -22,21 +22,24 @@ namespace xo {
using ppindentinfo = xo::print::ppindentinfo;
public:
explicit DExpectExprSsm(bool allow_defs,
bool cxl_on_rightparen);
DExpectExprSsm(bool allow_defs,
bool cxl_on_rightbrace,
bool cxl_on_rightparen);
static DExpectExprSsm * _make(DArena & parser_mm,
bool allow_defs,
bool cxl_on_rightbrace);
bool cxl_on_rightbrace,
bool cxl_on_rightparen);
/** create fop referring to new DExpectExprSsm **/
static obj<ASyntaxStateMachine,DExpectExprSsm> make(DArena & parser_mm,
bool allow_defs,
bool cxl_on_rightbrace);
bool cxl_on_rightbrace,
bool cxl_on_rightparen);
static void start(DArena & parser_mm,
bool allow_defs,
static void start(bool allow_defs,
bool cxl_on_rightbrace,
bool cxl_on_rightparen,
ParserStateMachine * p_psm);
static void start(ParserStateMachine * p_psm);
@ -46,6 +49,7 @@ namespace xo {
static const char * ssm_classname() { return "DExpectExprSsm"; }
bool allow_defs() const noexcept { return allow_defs_; }
bool cxl_on_rightbrace() const noexcept { return cxl_on_rightbrace_; }
bool cxl_on_rightparen() const noexcept { return cxl_on_rightparen_; }
///@}
/** @defgroup scm-expectexpr-methods general methods **/
@ -57,6 +61,15 @@ namespace xo {
void on_leftparen_token(const Token & tk,
ParserStateMachine * p_psm);
/** update state for this syntax on incoming rightparen token @p tk,
* with overall parser state in @p p_psm.
*
* Generally treats as illegal, but cancels gracefully when
* @ref cxl_on_rightparen_ set.
**/
void on_rightparen_token(const Token & tk,
ParserStateMachine * p_psm);
/** update state for this syntax on incoming leftbrace token @p tk,
* with overall parser state in @p p_psm
**/
@ -165,8 +178,11 @@ namespace xo {
* 2a. expression
**/
bool cxl_on_rightbrace_ = false;
/** if true: expecting either:
* 1a. expression
* 1b. right paren ')', in which case no expression
**/
bool cxl_on_rightparen_ = false;
};
} /*namespace scm*/
} /*namespace xo*/