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xo-parser: prep: semicolon expr separator, prep for infix ops

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This commit is contained in:
Roland Conybeare 2024-08-06 23:09:05 -04:00
commit 37268113fb
6 changed files with 409 additions and 60 deletions
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92
include/xo/reader/parser.hpp
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@ -30,6 +30,8 @@ namespace xo {
expect_symbol,
expect_type,
expr_progress,
n_exprstatetype
};
@ -58,18 +60,29 @@ namespace xo {
public:
exprstate() = default;
exprstate(exprstatetype exs_type,
rp<DefineExprAccess> def_expr = nullptr)
rp<Expression> candidate_expr,
rp<DefineExprAccess> def_expr)
: exs_type_{exs_type},
gen_expr_{std::move(candidate_expr)},
def_expr_{std::move(def_expr)} {}
static exprstate expect_toplevel_expression_sequence() {
return exprstate(exprstatetype::expect_toplevel_expression_sequence);
return exprstate(exprstatetype::expect_toplevel_expression_sequence, nullptr, nullptr);
}
static exprstate def_0() {
return exprstate(exprstatetype::def_0);
static exprstate expect_rhs_expression() {
return exprstate(exprstatetype::expect_rhs_expression, nullptr, nullptr);
}
static exprstate expect_symbol() {
return exprstate(exprstatetype::expect_symbol);
return exprstate(exprstatetype::expect_symbol, nullptr, nullptr);
}
static exprstate expect_type() {
return exprstate(exprstatetype::expect_type, nullptr, nullptr);
}
static exprstate make_expr_progress(rp<Expression> expr) {
return exprstate(exprstatetype::expr_progress, expr, nullptr);
}
static exprstate def_0(rp<DefineExprAccess> def_expr) {
return exprstate(exprstatetype::def_0, nullptr, def_expr);
}
exprstatetype exs_type() const { return exs_type_; }
@ -82,8 +95,14 @@ namespace xo {
bool admits_symbol() const;
/** true iff this parsing state admits a colon as next token **/
bool admits_colon() const;
/** true iff this parsing state admits a semicolon as next token **/
bool admits_semicolon() const;
/** true iff this parsing state admits a singleassign '=' as next token **/
bool admits_singleassign() const;
#ifdef NOT_YET
/** true iff this parsing state admits a leftparen '(' as next token **/
bool admits_leftparen() const;
#endif
/** true iff this parsing state admits a 64-bit floating point literal token **/
bool admits_f64() const;
@ -112,16 +131,23 @@ namespace xo {
exprstatestack * p_stack,
rp<Expression> * p_emit_expr);
void on_colon(exprstatestack * p_stack);
void on_semicolon(exprstatestack * p_stack,
rp<Expression> * p_emit_expr);
void on_singleassign(exprstatestack * p_stack);
#ifdef NOT_YET
void on_leftparen(exprstatestack * p_stack,
rp<Expression> * p_emit_expr);
#endif
void on_f64(const token_type & tk,
exprstatestack * p_stack,
rp<Expression> * p_emit_expr);
private:
/**
* def foo : f64 = 1
* ^ ^ ^ ^ ^ ^ ^
* | | | | | | (done)
* def foo : f64 = 1 ;
* ^ ^ ^ ^ ^ ^ ^ ^
* | | | | | | | (done)
* | | | | | | ??
* | | | | | def_4:expect_rhs_expression
* | | | | def_3
* | | | def_2:expect_type
@ -139,6 +165,8 @@ namespace xo {
**/
exprstatetype exs_type_;
/** generic expression **/
rp<Expression> gen_expr_;
/** scaffold a define-expression here **/
rp<DefineExprAccess> def_expr_;
/** scafford a convert-expression here.
@ -199,10 +227,10 @@ namespace xo {
* decltype point
*
* // forward declarations
* decl pi : f64
* decl fib(n : i32) -> i32
* decl pi : f64;
* decl fib(n : i32) -> i32;
*
* def pi = 3.14159265 // constant. = is single assignment
* def pi = 3.14159265; // constant. = is single assignment
*
* def fib(n : i32) -> i32 {
* // nested defs ok
@ -211,33 +239,37 @@ namespace xo {
* // (n == 0) ? s1 : aux(n - 1, s1 + s2, s1)
* //
* if (n == 0) {
* s1
* s1;
* } else {
* aux(n - 1, s1 + s2, s1)
* aux(n - 1, s1 + s2, s1);
* }
*
* // or:
* // if (n == 0) ? s1 : aux(n - 1, s1 + s2, s1)
* }
*
* aux(n=n, s1=1, s2=0)
* aux(n=n, s1=1, s2=0);
* }
*
* def anotherfib = lambda(n : i32) { fib(n) }
* def x := "fu"; // non-constant
* x += "bar";
*
* def any : object
* def l : list<object> = '()
* def anotherfib = lambda(n : i32) { fib(n) };
*
* deftype point :: {x : f64, y : f64}
* deftype polar :: {arg : f64, mag : f64}
* def any : object;
* def l : list<object> = '();
*
* deftype point :: {x : f64, y : f64};
* deftype polar :: {arg : f64, mag : f64};
*
* def polar2rect(pt : polar) -> point {
* point(x = pt.mag * cos(arg),
* y = pt.mag * sin(arg))
* y = pt.mag * sin(arg));
* }
*
* Grammar:
* toplevel-program = expression*
* toplevel-program = $expression(1); ..; $expression(n)
*
* type-decl = decltype $typename [<$tp1 .. $tpn>]
* expression = define-expr
* | literal-expr
@ -245,6 +277,7 @@ namespace xo {
* | apply-expr
* | if-expr
* | lambda-expr
* | arithmetic-expr
* | block
*
* define-expr = type-decl
@ -297,6 +330,23 @@ namespace xo {
* ..,
* $paramname(n) : $type(n)) body-expr
* body-expr = expression
*
* arithmetic-expr = expression binop expression
*
* binop = +
* | -
* | *
* | /
* | |
* | &
* | ^
* | ==
* | !=
* | <
* | <=
* | =>
* | >
*
**/
class parser {
public: