diff --git a/c/draft-release-notes.md b/c/draft-release-notes.md
index 0af20a055..c9c7c1097 100644
--- a/c/draft-release-notes.md
+++ b/c/draft-release-notes.md
@@ -49,3 +49,5 @@ longer-term follow-on [**issue 151**](https://github.com/johnkerl/miller/issues/
 * [**Issue 161**](https://github.com/johnkerl/miller/issues/161) fixes a CSV-parse error (with error message "unwrapped double quote at line 0") when a CSV file starts with the UTF-8 bill-of-materials ("BOM") sequence `0xef` `0xbb` `0xbf` and the header line has double-quoted fields. ([Release 5.2.0](https://github.com/johnkerl/miller/releases/tag/v5.2.0) introduced handling for UTF-8 BOMs, but missed the case of double-quoted header line.)
 
 * [**Issue 162**](https://github.com/johnkerl/miller/issues/162) fixes a corner case doing multi-emit of aggregate variables when the first variable name is a typo.
+
+There is no prebuilt Windows executable for this release; my apologies.
diff --git a/c/input/lrec_reader_mmap_xtab.c b/c/input/lrec_reader_mmap_xtab.c
index 43e9c4c64..b48dbe0f0 100644
--- a/c/input/lrec_reader_mmap_xtab.c
+++ b/c/input/lrec_reader_mmap_xtab.c
@@ -147,7 +147,6 @@ static lrec_t* lrec_parse_mmap_xtab_single_ifs_single_ips(file_reader_mmap_state
 	char* comment_string = pstate->comment_string;
 	int comment_string_length = pstate->comment_string_length;
 
-	// xxx more
 	if (pstate->do_auto_line_term) {
 		// Skip over otherwise empty LF-only or CRLF-only lines.
 		while (phandle->sol < phandle->eof) {
@@ -334,8 +333,6 @@ static lrec_t* lrec_parse_mmap_xtab_single_ifs_multi_ips(file_reader_mmap_state_
 			phandle->sol++;
 	}
 
-	// xxx skip comments ...
-
 	if (phandle->sol >= phandle->eof)
 		return NULL;
 
@@ -472,7 +469,6 @@ static lrec_t* lrec_parse_mmap_xtab_multi_ifs_single_ips(file_reader_mmap_state_
 		if (!skipped_anything)
 			break;
 	}
-	// xxx skip comments ...
 
 	if (phandle->sol >= phandle->eof)
 		return NULL;
diff --git a/c/oo b/c/oo
index 882219e7f..12577114c 100755
--- a/c/oo
+++ b/c/oo
@@ -36,10 +36,77 @@ flags="-a"
 #vee=-v
 vee=
 
-# ----------------------------------------------------------------
-announce
+## ----------------------------------------------------------------
+#announce XTAB
+#
+#mention input comments1.xtab
+#cat reg_test/input/comments/comments1.xtab
+#
+#mention skip comments1.xtab
+#run_mlr --skip-comments --ixtab --odkvp cat < reg_test/input/comments/comments1.xtab
+#run_mlr --skip-comments --ixtab --odkvp cat   reg_test/input/comments/comments1.xtab
+#
+#mention pass comments1.xtab
+#run_mlr --pass-comments --ixtab --odkvp cat < reg_test/input/comments/comments1.xtab
+#run_mlr --pass-comments --ixtab --odkvp cat   reg_test/input/comments/comments1.xtab
+#
+#mention input comments2.xtab
+#cat reg_test/input/comments/comments2.xtab
+#
+#mention skip comments2.xtab
+#run_mlr --skip-comments --ixtab --odkvp cat < reg_test/input/comments/comments2.xtab
+#run_mlr --skip-comments --ixtab --odkvp cat   reg_test/input/comments/comments2.xtab
+#
+#mention pass comments2.xtab
+#run_mlr --pass-comments --ixtab --odkvp cat < reg_test/input/comments/comments2.xtab
+#run_mlr --pass-comments --ixtab --odkvp cat   reg_test/input/comments/comments2.xtab
 
-run_mlr --from $indir/abixy --opprint stats1 -a sum --gr '[a-h]' --fr '[i-z]'
-run_mlr --from $indir/abixy --opprint stats1 -a sum  -g  a,b     --fr '[i-z]'
-run_mlr --from $indir/abixy --opprint stats1 -a sum --gr '[a-h]'  -f  i,x,y
-run_mlr --from $indir/abixy --opprint stats1 -a sum --grfx '[a-h]'
+## ----------------------------------------------------------------
+#announce DKVP
+#
+#mention input comments1.dkvp
+#cat reg_test/input/comments/comments1.dkvp
+#
+#mention skip comments1.dkvp
+#run_mlr --skip-comments --idkvp --oxtab cat < reg_test/input/comments/comments1.dkvp
+#run_mlr --skip-comments --idkvp --oxtab cat   reg_test/input/comments/comments1.dkvp
+#
+#mention pass comments1.dkvp
+#run_mlr --pass-comments --idkvp --oxtab cat < reg_test/input/comments/comments1.dkvp
+#run_mlr --pass-comments --idkvp --oxtab cat   reg_test/input/comments/comments1.dkvp
+#
+#mention input comments2.dkvp
+#cat reg_test/input/comments/comments2.dkvp
+#
+#mention skip comments2.dkvp
+#run_mlr --skip-comments --idkvp --oxtab cat < reg_test/input/comments/comments2.dkvp
+#run_mlr --skip-comments --idkvp --oxtab cat   reg_test/input/comments/comments2.dkvp
+#
+#mention pass comments2.dkvp
+#run_mlr --pass-comments --idkvp --oxtab cat < reg_test/input/comments/comments2.dkvp
+#run_mlr --pass-comments --idkvp --oxtab cat   reg_test/input/comments/comments2.dkvp
+
+# ----------------------------------------------------------------
+announce NIDX
+
+mention input comments1.nidx
+cat reg_test/input/comments/comments1.nidx
+
+mention skip comments1.nidx
+run_mlr --skip-comments --inidx --oxtab cat < reg_test/input/comments/comments1.nidx
+run_mlr --skip-comments --inidx --oxtab cat   reg_test/input/comments/comments1.nidx
+
+mention pass comments1.nidx
+run_mlr --pass-comments --inidx --oxtab cat < reg_test/input/comments/comments1.nidx
+run_mlr --pass-comments --inidx --oxtab cat   reg_test/input/comments/comments1.nidx
+
+mention input comments2.nidx
+cat reg_test/input/comments/comments2.nidx
+
+mention skip comments2.nidx
+run_mlr --skip-comments --inidx --oxtab cat < reg_test/input/comments/comments2.nidx
+run_mlr --skip-comments --inidx --oxtab cat   reg_test/input/comments/comments2.nidx
+
+mention pass comments2.nidx
+run_mlr --pass-comments --inidx --oxtab cat < reg_test/input/comments/comments2.nidx
+run_mlr --pass-comments --inidx --oxtab cat   reg_test/input/comments/comments2.nidx
diff --git a/c/reg_test/input/Makefile.am b/c/reg_test/input/Makefile.am
index 8fd7f7b99..d5b72ab0f 100644
--- a/c/reg_test/input/Makefile.am
+++ b/c/reg_test/input/Makefile.am
@@ -1,4 +1,6 @@
-SUBDIRS=	rfc-csv
+SUBDIRS=	rfc-csv \
+		comments
+
 EXTRA_DIST=	\
 		a.csv \
 		a.pprint \
@@ -25,6 +27,7 @@ EXTRA_DIST=	\
 		c.pprint \
 		capture-lengths.dkvp \
 		capture.dkvp \
+		comments \
 		d.csv \
 		d.pprint \
 		date1.csv \
diff --git a/c/reg_test/input/comments/Makefile.am b/c/reg_test/input/comments/Makefile.am
new file mode 100644
index 000000000..b2da0b476
--- /dev/null
+++ b/c/reg_test/input/comments/Makefile.am
@@ -0,0 +1,11 @@
+EXTRA_DIST=	\
+	comments1.dkvp \
+	comments2.dkvp \
+	comments3.dkvp \
+	\
+	comments1.nidx \
+	comments2.nidx \
+	comments3.nidx \
+	\
+	comments1.xtab \
+	comments2.xtab
diff --git a/c/reg_test/input/comments/comments1.dkvp b/c/reg_test/input/comments/comments1.dkvp
new file mode 100644
index 000000000..9c3dad9cf
--- /dev/null
+++ b/c/reg_test/input/comments/comments1.dkvp
@@ -0,0 +1,3 @@
+# hello world 1
+a=1,b=2,c=3
+a=4,b=5,c=6
diff --git a/c/reg_test/input/comments/comments1.nidx b/c/reg_test/input/comments/comments1.nidx
new file mode 100644
index 000000000..eb2f2f10d
--- /dev/null
+++ b/c/reg_test/input/comments/comments1.nidx
@@ -0,0 +1,3 @@
+# hello world 1
+aX1 bX2 cX3
+aX4 bX5 cX6
diff --git a/c/reg_test/input/comments/comments1.xtab b/c/reg_test/input/comments/comments1.xtab
new file mode 100644
index 000000000..4d9f43db8
--- /dev/null
+++ b/c/reg_test/input/comments/comments1.xtab
@@ -0,0 +1,8 @@
+x 1
+#hello world3
+z 3
+
+x 2
+#hello world4
+z 5
+
diff --git a/c/reg_test/input/comments/comments2.dkvp b/c/reg_test/input/comments/comments2.dkvp
new file mode 100644
index 000000000..b13f182fb
--- /dev/null
+++ b/c/reg_test/input/comments/comments2.dkvp
@@ -0,0 +1,3 @@
+a=1,b=2,c=3
+# hello world 2
+a=4,b=5,c=6
diff --git a/c/reg_test/input/comments/comments2.nidx b/c/reg_test/input/comments/comments2.nidx
new file mode 100644
index 000000000..8ee3ae723
--- /dev/null
+++ b/c/reg_test/input/comments/comments2.nidx
@@ -0,0 +1,3 @@
+aX1 bX2 cX3
+# hello world 2
+aX4 bX5 cX6
diff --git a/c/reg_test/input/comments/comments2.xtab b/c/reg_test/input/comments/comments2.xtab
new file mode 100644
index 000000000..043e7736b
--- /dev/null
+++ b/c/reg_test/input/comments/comments2.xtab
@@ -0,0 +1,13 @@
+#hello world1
+
+#hello world2
+x 1
+#hello world3
+z 3
+
+x 2
+#hello world4
+z 5
+#hello world5
+
+#hello world6
diff --git a/c/reg_test/input/comments/comments3.dkvp b/c/reg_test/input/comments/comments3.dkvp
new file mode 100644
index 000000000..23c5e97c8
--- /dev/null
+++ b/c/reg_test/input/comments/comments3.dkvp
@@ -0,0 +1,3 @@
+a=1,b=2,c=3
+a=4,b=5,c=6
+# hello world 3
diff --git a/c/reg_test/input/comments/comments3.nidx b/c/reg_test/input/comments/comments3.nidx
new file mode 100644
index 000000000..2d23d575d
--- /dev/null
+++ b/c/reg_test/input/comments/comments3.nidx
@@ -0,0 +1,3 @@
+aX1 bX2 cX3
+aX4 bX5 cX6
+# hello world 3
diff --git a/c/todo.txt b/c/todo.txt
index 6ed3da5a2..bc8e0a782 100644
--- a/c/todo.txt
+++ b/c/todo.txt
@@ -11,8 +11,6 @@ BUGFIXES
   x=9223372036854775802,y=-9223372036854775806
   x=9223372036854775805,y=-9223372036854775802
 
-$ mlr --from s put 'tee > "boo.".$a, mapexcept($*,"a")'
-
 ================================================================
 5.3.0 TO DO:
 
@@ -22,25 +20,35 @@ $ mlr --from s put 'tee > "boo.".$a, mapexcept($*,"a")'
   o streqn-past-eof scenarios @ page boundaries ...
   o UT for skip/pass
 
-    input/lrec_reader_mmap_csv.c:9
-    input/lrec_reader_mmap_csvlite.c:37
-    input/lrec_reader_mmap_dkvp.c:25
-    input/lrec_reader_mmap_json.c:7
-    input/lrec_reader_mmap_nidx.c:10
-    input/lrec_reader_mmap_xtab.c:47
+  k input/lrec_reader_mmap_dkvp.c:25
+  k input/lrec_reader_stdio_dkvp.c:21
 
-    input/lrec_reader_stdio_csv.c:9
-    input/lrec_reader_stdio_csvlite.c:13
-    input/lrec_reader_stdio_dkvp.c:21
-    input/lrec_reader_stdio_json.c:7
-    input/lrec_reader_stdio_nidx.c:21
+  k input/lrec_reader_mmap_nidx.c:10
+  k input/lrec_reader_stdio_nidx.c:21
+
+    input/lrec_reader_mmap_xtab.c:47
     input/lrec_reader_stdio_xtab.c:8
 
+    input/lrec_reader_mmap_csv.c:9
+    input/lrec_reader_stdio_csv.c:9
+
+    input/lrec_reader_mmap_csvlite.c:37
+    input/lrec_reader_stdio_csvlite.c:13
+
+    input/lrec_reader_mmap_json.c:7
+    input/lrec_reader_stdio_json.c:7
+
   o mlh
   o mld
-* sql in/outs -> own page?
+
 * sql-setup doc somewhere .......
 
+* ./configure
+
+* valgrinds
+
+* xxxes
+
 ================================================================
 FUNDAM:
 
@@ -160,7 +168,7 @@ MAPVAR CHECKLIST:
 * clarify ownership semantics in localstack & mlhmmv via function names, & top-of-file comments
 
 ================================================================
-5.3.0 ideas:
+5.4.0 ideas:
 
 ----------------------------------------------------------------
 ! multi-field x many verbs: -f/-r field-name-spec opportunities throughout
@@ -198,8 +206,6 @@ which verbs:
 
 * mt_error/fatal/skip-assign audit
 
-* perf note: DSL stuff performant w/r/t ruby/python (mand bench & maybe others)
-
 ! more than 'syntax error' from lemon-parse failures ... lemon API research
 
 ? some sort of debug/single-step/trace ... include the AST in the CST & reverse-generate ?
@@ -260,7 +266,7 @@ COMPARES:
 * https://www.gnu.org/software/datamash/manual/datamash.html
 
 ================================================================
-5.3.0 IDEAS:
+5.4.0 IDEAS:
 
 !! coroutines: line-oriented; operate on field(s); r/w popen