ludic/packages/ludic.ui/expr_parse.ludic

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# expr_parse.ludic - a condition, or/and/not, a comparison, sums and products, then a name
# with its members, indexes and calls
function px_cond(r: UiRd) -> UiExpr {
let a = px_or(r)
if not rd_op(r, "?") { return a }
let e = ex_new(X_COND)
e.a = a
e.b = px_cond(r)
if not rd_op(r, ":") { rd_fail(r, "':'") }
e.c = px_cond(r)
return e
}
function px_or(r: UiRd) -> UiExpr {
var a = px_and(r)
while rd_word(r, "or") or rd_op(r, "||") {
let e = ex_new(X_OR)
e.a = a
e.b = px_and(r)
a = e
}
return a
}
function px_and(r: UiRd) -> UiExpr {
var a = px_not(r)
while rd_word(r, "and") or rd_op(r, "&&") {
let e = ex_new(X_AND)
e.a = a
e.b = px_not(r)
a = e
}
return a
}
function px_not(r: UiRd) -> UiExpr {
rd_ws(r)
if rd_word(r, "not") or (rd_c(r, 0) == 33 and rd_c(r, 1) != 61 and rd_op(r, "!")) {
let e = ex_new(X_NOT)
e.a = px_not(r)
return e
}
return px_cmp(r)
}
function px_bin(op: string, a: UiExpr, b: UiExpr) -> UiExpr {
let e = ex_new(X_BIN)
e.s = op
e.a = a
e.b = b
return e
}
function px_cmp(r: UiRd) -> UiExpr {
let a = px_sum(r)
# literals, longest first: a list of them was made on every call
if rd_op(r, "==") { return px_bin("==", a, px_sum(r)) }
if rd_op(r, "!=") { return px_bin("!=", a, px_sum(r)) }
if rd_op(r, "<=") { return px_bin("<=", a, px_sum(r)) }
if rd_op(r, ">=") { return px_bin(">=", a, px_sum(r)) }
if rd_op(r, "<") { return px_bin("<", a, px_sum(r)) }
if rd_op(r, ">") { return px_bin(">", a, px_sum(r)) }
return a
}
function px_sum(r: UiRd) -> UiExpr {
var a = px_prod(r)
while true {
if rd_op(r, "+") { a = px_bin("+", a, px_prod(r)) } else if rd_op(r, "-") { a = px_bin("-", a, px_prod(r)) } else { return a }
}
return a
}
function px_prod(r: UiRd) -> UiExpr {
var a = px_unary(r)
while true {
if rd_op(r, "*") { a = px_bin("*", a, px_unary(r)) } else if rd_op(r, "/") { a = px_bin("/", a, px_unary(r)) } else if rd_op(r, "%") { a = px_bin("%", a, px_unary(r)) } else { return a }
}
return a
}
function px_unary(r: UiRd) -> UiExpr {
if rd_op(r, "-") {
let e = ex_new(X_NEG)
e.a = px_unary(r)
return e
}
return px_post(r)
}
function px_post(r: UiRd) -> UiExpr {
var a = px_primary(r)
while r.err == "" {
if rd_op(r, ".") {
let e = ex_new(X_MEMBER)
e.a = a
e.s = rd_name(r)
a = e
} else if rd_op(r, "[") {
let e = ex_new(X_INDEX)
e.a = a
e.b = px_cond(r)
if not rd_op(r, "]") { rd_fail(r, "']'") }
a = e
} else { return a }
}
return a
}