Parse regex modifiers and complain about NYI ones

src/niecza

@@ -27,6 +27,82 @@ use Operator;
 use OptRxSimple;
 use Sig;
 
+augment class NieczaActions {
+method quote:rx ($/) {
+    self.extract_rx_adverbs(False, False, $<quibble>);
+    make self.op_for_regex($/, $<quibble>.ast);
+}
+method quote:m  ($/) {
+    make ::Op::CallMethod.new(|node($/), name => 'ACCEPTS',
+            receiver => self.op_for_regex($/, $<quibble>.ast),
+            args => [ mklex($/, '$_'),
+                self.extract_rx_adverbs(True, False, $<quibble>) ]);
+}
+method regex_block($/) {
+    if $<onlystar> {
+        return Nil;
+    }
+    self.extract_rx_adverbs(False, False, $<quotepair>);
+    make $<nibble>.ast;
+}
+method sibble($/) {
+    my $regex = self.op_for_regex($/, $<left>.ast);
+    my $repl;
+    if $<infixish> {
+        if $<infixish> eq '=' {
+            $repl = $<right>.ast;
+        } elsif $<infixish>.ast ~~ ::Operator::CompoundAssign {
+            $repl = $<infixish>.ast.base.with_args($/,
+                mkcall($/, '&prefix:<~>', ::Op::ContextVar.new(name => '$*/')),
+                $<right>.ast);
+        } else {
+            $/.CURSOR.sorry("Unhandled operator in substitution");
+            $repl = mklex($/, 'Any');
+        }
+    } else {
+        $repl = $<right>.ast;
+    }
+    $repl = self.transparent($/, $repl);
+    make ::Op::CallSub.new(|node($/), invocant => mklex($/,'&_substitute'),
+        args => [ mklex($/, '$_'), $regex, $repl,
+            self.extract_rx_adverbs(True, True, $/) ]);
+}
+
+method extract_rx_adverbs($ismatch, $issubst, $match) {
+    my $qps = ($match ~~ List) ?? $match !! $match<babble><quotepair>;
+    return () if !$qps;
+
+    my @ok;
+    my @nyi;
+    my @args;
+    my @internal = < sigspace s ratchet r ignorecase i >;
+
+    push @nyi, < ignoreaccent a bytes codes graphs chars Perl5 P5 >;
+
+    if $issubst {
+        push @nyi, < sameaccent aa samecase ii th st nd rd nth x >;
+    }
+
+    if $ismatch {
+        push @nyi, < overlap ov exhaustive ex continue c pos p global g rw >;
+    }
+
+    for @$qps -> $qp {
+        if @internal.grep($qp<k>) {
+            # handled by rx compiler
+        } elsif @ok.grep($qp<k>) {
+            push @args, $qp.ast
+        } elsif @nyi.grep($qp<k>) {
+            $qp.CURSOR.sorry("Regex modifier $qp<k> not yet implemented");
+        } else {
+            $qp.CURSOR.sorry("Regex modifier $qp<k> not valid on { $issubst ?? "substitution" !! $ismatch ?? "match" !! "regex literal" }");
+        }
+    }
+
+    @args
+}
+}
+
 augment class Op::Labelled { #OK exist
     method statement_level() {
         self.new(name => $.name, stmt => $.stmt.statement_level);