diff --git a/c/mapping/lrec_evaluators.c b/c/mapping/lrec_evaluators.c
index c752af1b4..cd05cd2ea 100644
--- a/c/mapping/lrec_evaluators.c
+++ b/c/mapping/lrec_evaluators.c
@@ -518,6 +518,7 @@ lrec_evaluator_t* lrec_evaluator_alloc_from_unary_func_name(char* function_name,
     } else if (streq(function_name, "toupper")) { return lrec_evaluator_alloc_from_s_s_func(s_s_toupper_func, parg1);
     } else if (streq(function_name, "sec2gmt")) { return lrec_evaluator_alloc_from_s_f_func(s_f_sec2gmt_func, parg1);
     } else if (streq(function_name, "gmt2sec")) { return lrec_evaluator_alloc_from_f_s_func(f_s_gmt2sec_func, parg1);
+    } else if (streq(function_name, "strlen"))  { return lrec_evaluator_alloc_from_s_f_func(f_s_strlen_func,  parg1);
 
 	} else return NULL; // xxx handle me better
 }
diff --git a/c/mapping/mlr_val.c b/c/mapping/mlr_val.c
index 5e0e01ff3..7c5d39042 100644
--- a/c/mapping/mlr_val.c
+++ b/c/mapping/mlr_val.c
@@ -214,6 +214,12 @@ mlr_val_t f_s_gmt2sec_func(mlr_val_t* pval1) {
 	return rv;
 }
 
+// ----------------------------------------------------------------
+mlr_val_t f_s_strlen_func(mlr_val_t* pval1) {
+	mlr_val_t rv = {.type = MT_DOUBLE, .u.double_val = strlen(pval1->u.string_val)};
+	return rv;
+}
+
 // ----------------------------------------------------------------
 // xxx cmt us!!!!
 
diff --git a/c/mapping/mlr_val.h b/c/mapping/mlr_val.h
index 7b41ba1f7..a638b6d00 100644
--- a/c/mapping/mlr_val.h
+++ b/c/mapping/mlr_val.h
@@ -180,6 +180,7 @@ mlr_val_t s_sss_sub_func(mlr_val_t* pval1, mlr_val_t* pval2, mlr_val_t* pval3);
 // ----------------------------------------------------------------
 mlr_val_t s_f_sec2gmt_func(mlr_val_t* pval1);
 mlr_val_t f_s_gmt2sec_func(mlr_val_t* pval1);
+mlr_val_t f_s_strlen_func(mlr_val_t* pval1);
 
 // ----------------------------------------------------------------
 mlr_val_t eq_op_func(mlr_val_t* pval1, mlr_val_t* pval2);
diff --git a/c/todo.txt b/c/todo.txt
index e35478ded..f48f48fb8 100644
--- a/c/todo.txt
+++ b/c/todo.txt
@@ -35,15 +35,10 @@ FEATURES/+
   -> move datadirs too ..... unify c & doc data dirs to parent?
   -> remove/coalesce/gzip the large data files
 
-* readme @ each level incl. sof et al. @ base
-  -> & perfopt: lrec_t not hashmap per se; stdio backings with minimal copying; mmap entirely; ... ?
-
 ! mlr sort CLI opt for choice of heap/merge/quick -- ?
 
 * mod op (either c-like, or sane) and put into wikidoc if so.
 
-? rip through filenames @ start & abend unless -f each: fail fast.
-
 ================================================================
 NEATEN
 
@@ -123,6 +118,7 @@ UT/REG
 * tac/X/tac for all X
 * multi-csv I/O: include --icsv --odkvp and --idkvp --ocsv, as well as --csv cases
 * het-xtab out
+* modulus
 
 ================================================================
 INTERNAL DOCS (e.g. README)