From 89921f7ea6dd2f6cd077a8e408cb31e4b5c07551 Mon Sep 17 00:00:00 2001
From: Jonathan Worthington <jnthn@jnthn.net>
Date: Tue, 7 Jul 2020 16:09:41 +0200
Subject: [PATCH] RakuAST for regex anchors

---
 src/Raku/Actions.nqp       | 30 ++++++++++++++++++++++++++++
 src/Raku/ast/regex.rakumod | 41 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)

diff --git a/src/Raku/Actions.nqp b/src/Raku/Actions.nqp
index 7088980f220..5df78410ac1 100644
--- a/src/Raku/Actions.nqp
+++ b/src/Raku/Actions.nqp
@@ -779,6 +779,12 @@ class Raku::RegexActions is HLL::Actions {
         $res := nqp::atkey($res.WHO, $t2) unless nqp::isnull($res);
         nqp::ifnull($res, nqp::die("No such node RakuAST::{$t1}::{$t2}"))
     }
+    multi method r($t1, $t2, $t3) {
+        my $res := nqp::atkey($ast_root, $t1);
+        $res := nqp::atkey($res.WHO, $t2) unless nqp::isnull($res);
+        $res := nqp::atkey($res.WHO, $t3) unless nqp::isnull($res);
+        nqp::ifnull($res, nqp::die("No such node RakuAST::{$t1}::{$t2}::{$t3}"))
+    }
 
     method nibbler($/) {
         make $<termseq>.ast;
@@ -866,4 +872,28 @@ class Raku::RegexActions is HLL::Actions {
             make self.r('Regex', 'Literal').new(~$/);
         }
     }
+
+    method metachar:sym<^>($/) {
+        make self.r('Regex', 'Anchor', 'BeginningOfString').new;
+    }
+
+    method metachar:sym<^^>($/) {
+        make self.r('Regex', 'Anchor', 'BeginningOfLine').new;
+    }
+
+    method metachar:sym<$>($/) {
+        make self.r('Regex', 'Anchor', 'EndOfString').new;
+    }
+
+    method metachar:sym<$$>($/) {
+        make self.r('Regex', 'Anchor', 'EndOfLine').new;
+    }
+
+    method metachar:sym<lwb>($/) {
+        make self.r('Regex', 'Anchor', 'LeftWordBoundary').new;
+    }
+
+    method metachar:sym<rwb>($/) {
+        make self.r('Regex', 'Anchor', 'RightWordBoundary').new;
+    }
 }
diff --git a/src/Raku/ast/regex.rakumod b/src/Raku/ast/regex.rakumod
index c3a152532cc..2bf67847473 100644
--- a/src/Raku/ast/regex.rakumod
+++ b/src/Raku/ast/regex.rakumod
@@ -121,3 +121,44 @@ class RakuAST::Regex::Literal is RakuAST::Regex::Atom {
         QAST::Regex.new( :rxtype<literal>, $!text )
     }
 }
+
+#| The base for all kinds of anchor.
+class RakuAST::Regex::Anchor is RakuAST::Regex::Atom {
+    method new() {
+        nqp::create(self)
+    }
+
+    method IMPL-REGEX-QAST(RakuAST::IMPL::QASTContext $context, %mods) {
+        QAST::Regex.new( :rxtype<anchor>, :subtype(self.IMPL-QAST-SUBTYPE) )
+    }
+}
+
+#| The beginning of string (^) anchor.
+class RakuAST::Regex::Anchor::BeginningOfString is RakuAST::Regex::Anchor {
+    method IMPL-QAST-SUBTYPE() { 'bos' }
+}
+
+#| The beginning of line (^^) anchor.
+class RakuAST::Regex::Anchor::BeginningOfLine is RakuAST::Regex::Anchor {
+    method IMPL-QAST-SUBTYPE() { 'bol' }
+}
+
+#| The end of string ($) anchor.
+class RakuAST::Regex::Anchor::EndOfString is RakuAST::Regex::Anchor {
+    method IMPL-QAST-SUBTYPE() { 'eos' }
+}
+
+#| The end of line (^^) anchor.
+class RakuAST::Regex::Anchor::EndOfLine is RakuAST::Regex::Anchor {
+    method IMPL-QAST-SUBTYPE() { 'eol' }
+}
+
+#| The left word boundary (<<) anchor.
+class RakuAST::Regex::Anchor::LeftWordBoundary is RakuAST::Regex::Anchor {
+    method IMPL-QAST-SUBTYPE() { 'lwb' }
+}
+
+#| The right word boundary (>>) anchor.
+class RakuAST::Regex::Anchor::RightWordBoundary is RakuAST::Regex::Anchor {
+    method IMPL-QAST-SUBTYPE() { 'rwb' }
+}