add some more nqp examples

Author: tbrowder

examples/sub-lines2words.nqp

@@ -0,0 +1,27 @@
+#!/usr/bin/env nqp
+
+# create a line => words splitting function
+my $line := ' #   one  two ';
+
+say("\$line: '$line'");
+
+my @w := words($line);
+
+say("'$line' => words");
+for @w {
+    say("  word: $_");
+}
+
+sub words($line) {
+    my @arr := nqp::split(' ', $line);
+    my @words := [];
+    for @arr {
+        my $s := $_;
+        # remove any whitespace
+        $s := subst($s, /\s+/, '', :global);
+        next if !$s;
+        @words.push($s);
+    }
+
+    return @words;
+}

examples/test-ws.nqp

@@ -0,0 +1,22 @@
+#!/usr/bin/env nqp
+
+# test regexes for deleting and normalizing whitespace in text
+# interspersed with comments
+my $txt := 'blah  # comment
+                # comment
+
+          blah';
+
+my $rx := /
+            <!after \S>
+            \h*
+            [
+            | [\h* '#' \N* \n]
+            | [\h* \n]
+            ]*
+            \h*
+          /;
+
+my $s := subst($txt, $rx, ' ');
+say("original text = '$txt'");
+say("new text = '$s'");

examples/use-classes.nqp

@@ -0,0 +1,103 @@
+#!/usr/bin/env nqp
+
+# based on blog post by Andrew Shitov:
+#
+#   https://perl6.online/2018/01/09/what-does-nqpgetattr-do/
+#
+#   class C {
+#       has $.attr is rw;
+#   }
+#
+#   my $o := nqp::create(C);
+#   $o.attr = 'other value';
+#   nqp::say(nqp::getattr($o, C, '$!attr')); # other value
+
+class Foo {
+    has $!line;
+    has @!contents;
+
+    method set-line($value) {
+        $!line := $value;
+    }
+
+    method set-contents(@value) {
+        @!contents := @value;
+    }
+
+    method add2contents($value) {
+        @!contents.push($value);
+    }
+
+    method empty-contents() {
+        @!contents := [];
+    }
+
+    # note the empty parens are required in the declaration
+    method show-line() {
+        say("  \$!line: '$!line'");
+    }
+
+    # note the empty parens are required in the declaration
+    method show-contents() {
+        say("  \@!contents:");
+        if !nqp::elems(@!contents) {
+            say("  [empty]");
+            return;
+        }
+        for @!contents {
+            say("    $_");
+        }
+    }
+}
+
+my $line1 := ' # text ';
+my $line2 := ' text ';
+
+my $o1 := nqp::create(Foo);
+$o1.set-line($line1);
+my $o2 := nqp::create(Foo);
+$o2.set-line($line2);
+
+my $L1 := nqp::getattr($o1, Foo, '$!line');
+my $L2 := nqp::getattr($o2, Foo, '$!line');
+say("\$o1.line: '$L1'");
+say("\$o2.line: '$L2'");
+
+my @arr := nqp::list(
+    'elem 0',
+    'elem 1',
+);
+
+$o1.set-contents(@arr);
+
+my @list := nqp::getattr($o1, Foo, '@!contents');
+say("\$o1's contents:");
+for @list {
+    say("  $_");
+}
+
+$o1.add2contents('another elem');
+@list := nqp::getattr($o1, Foo, '@!contents');
+say("\n\$o1's contents after an update:");
+for @list {
+    say("  $_");
+}
+
+$o1.empty-contents;
+@list := nqp::getattr($o1, Foo, '@!contents');
+say("\n\$o1's contents after emptying:");
+if !nqp::elems(@list) {
+    say("  \$o1's \@contents are empty");
+}
+else {
+    for @list {
+        say("  $_");
+    }
+}
+
+my $o3:= nqp::create(Foo);
+$o3.set-contents(@arr);
+$o3.set-line('line 3');
+
+$o3.show-contents;
+$o3.show-line;

examples/use-hashes.nqp

@@ -0,0 +1,31 @@
+#!/usr/bin/env nqp
+
+# create a hash
+my %h := nqp::hash(
+  'k1', 0,
+  'k2', 1,
+);
+
+# iterate over the hash
+for %h {
+    my $k := nqp::iterkey_s($_); 
+    my $v := nqp::iterval($_);
+    say("key $k => val $v");
+}
+
+my $k1 := 'k1';
+my $k2 := 'k2';
+
+# return value of a key
+my $v := nqp::atkey(%h, $k1);
+say("value of key $k1 is $v");
+
+# check existence of a key
+
+if nqp::existskey(%h, $k2) {
+    say("key $k2 exists");
+}
+
+
+
+