Add unlines

README.md

@@ -14,13 +14,113 @@ Best way to understand purpose and syntax of `mshell` is to see it in action. He
 
 *Better Awk One-liners*. Examples from the `awk` book, translated to `mshell`
 
-| Objective | `awk` | `mshell` |
-|-----------|-------|----------|
-| Print the total number of input lines             | `END { print NR }`                    | `.. len wl` |
-| Print the 10th input line                         | `NR == 10`                            | `.. :10: wl` (Failure if < 10 lines) |
-| Print the last field of every input line          | `{ print $NF }`                       | `.. (ws split :-1: wl) each` |
-| Print the last field of the last input line       | `{ field = $NF } END { print field }` | `.. :-1: (ws split :-1: wl)` |
-| Print every input line with more than four fields | `NF > 4`                              | `.. dup (ws split) map (len 4 >) filter (" " join) map unlines w`  |
+```sh
+# 1. Print the total nubmer of input lines:
+# END { print NR }
+.. len wl
+
+# 2. Print the 10th input line:
+# NR == 10
+.. :10: wl
+
+# 3. Print the last field of every input line:
+# { print $NF }
+.. (ws split :-1: wl) each
+
+# 4. Print the last field of the last input line:
+#     { field = $NF }
+# END { print field }
+.. :-1: " " split :-1: wl
+
+# 5. Print every input line with more than four fields
+# NF > 4
+.. (dup ws split len [(4 >) (wl) (drop)] if) each
+
+# 6. Print every input line in which the last field is more than 4
+# $NF > 4
+.. (ws split) map (:-1: toFloat 4 >) filter unlines wl
+
+# 7. Print the total number of fields in all input lines
+#     { nf = nf + $NF }
+# END { print nf }
+.. (ws split len) map sum wl
+
+# 8. Print the total number of lines that contain 'Beth'
+# /Beth/ { nlines = nlines + 1 }
+# END { print nlines }
+.. ("Beth" in) filter len wl
+
+# 9. Print the largest first field and the line that contains it (assumes some $1 is positive):
+# $1 > max { max = $1; line = $0 }
+# END      { print max, line }
+
+0 @max
+..
+# line first
+(dup " " split :1: toFloat [(dup max! >) (@max @line)] if)
+each max! w " " w line! w
+
+# 10. Print every line that has at least one field
+# NF > 0
+.. (len 0 >) filter (wl) each
+
+# 11. Print every line longer than 80 characters
+# length($0) > 80
+.. (len 80 >) filter (wl) each
+
+# 12. Print the number of fields in every line followed by the line itself
+# { print NF, $0 }
+.. (dup " " split len w " " w wl) each
+
+# 13. Print the first two fields in opposite order, of every line
+# { print $2, $1 }
+.. (" " split :1: :2: w w) each
+
+# 14. Exchange the first two fields of every line and then print the line
+# { temp = $1; $1 = $2; $2 = temp; print }
+# Need a way to write value into an index.
+# .. (dup " " split :1: :2: swap w w) each
+
+# 15. Print every line with the first field replaced by the line number
+# { $1 = NR; print }
+# Need a way to write value into an index.
+# .. (dup w 1 w w) each
+
+# 16. Print every line after erasing the second field
+# { $2 = ""; print }
+# Need a way to delete at an index.
+
+# 17. Print in reverse order the fields of every line
+# { for (i = NF; i > 0; i = i - 1) printf "%s ", $i
+# printf "\n"
+# }
+.. (" " split reverse " " join wl) each
+
+# 18. Print the sums of the fields of every line
+# { sum = 0
+#   for (i = 1; i <= NF; i = i + 1) sum = sum + $i
+#   print sum
+# }
+.. (" " split (toFloat) map sum wl) each
+
+# 19. Add up all fields in all lines and print the sum
+# { for (i = 1; i <= NF; i = i + 1) sum = sum + $i }
+# END { print sum }
+.. (" " split (toFloat) map sum) map sum wl
+
+# 20. Print every line after replacing each field by its absolute value
+# { for (i = 1; i <= NF; i = i + 1) $i = ($i < 0) ? -$i : $i; print }
+.. (" " split (toFloat abs) map " " join wl) each
+
+```
+
+<!-- | Objective | `awk` | `mshell` | -->
+<!-- |-----------|-------|----------| -->
+<!-- | Print the total number of input lines             | `END { print NR }`                    | `.. len wl` | -->
+<!-- | Print the 10th input line                         | `NR == 10`                            | `.. :10: wl` (Failure if < 10 lines) | -->
+<!-- | Print the last field of every input line          | `{ print $NF }`                       | `.. (ws split :-1: wl) each` | -->
+<!-- | Print the last field of the last input line       | `{ field = $NF } END { print field }` | `.. :-1: (ws split :-1: wl)` | -->
+<!-- | Print every input line with more than four fields | `NF > 4`                              | `.. (dup ws split len [(4 >) (wl) (drop)] if) each`  | -->
 
 
 *Simpler execution of common shell idioms*

examples/awk.msh

@@ -2,15 +2,15 @@
 
 # 1. Print the total nubmer of input lines:
 # END { print NR }
-stdin lines len wl
+.. len wl
 
 # 2. Print the 10th input line:
 # NR == 10
-stdin lines :10: wl
+.. :10: wl
 
 # 3. Print the last field of every input line:
 # { print $NF }
-stdin lines (" " split :-1: wl) each
+.. (" " split :-1: wl) each
 
 # 4. Print the last field of the last input line:
 #     { field = $NF }
@@ -19,7 +19,7 @@ stdin lines :-1: " " split :-1: wl
 
 # 5. Print every input line with more than four fields
 # NF > 4
-stdin lines (" " split) map (len 4 >) filter unlines wl
+.. (dup " " split len [(4 >) (wl) (drop)] if) each
 
 # 6. Print every input line in which the last field is more than 4
 # $NF > 4

lib/std.msh

@@ -1,6 +1,6 @@
 # Standard library for mshell
 
-# each (list quote --)
+# each (list quote: (item --) --)
 def each 
     over len each-len! # Get total length
     0 each-idx! # index
@@ -60,6 +60,17 @@ def .. stdin lines end
 # tt = Tab separated Table (-- list[list[str]])
 def tt stdin lines ("	" split) map end
 
+# unlines (list[str] -- str)
+def unlines 
+    [] unlines-accum! # Accumulator
+    (
+        @unlines-accum append
+       "\n" append
+       drop
+    ) each
+    @unlines-accum "" join
+end
+
 # map (list quote -- list)
 # [seq 1 1000]o; ("Line #" over str + wl) each
 # [1 2 3] (2 +) map .s

tests/unlines.msh

@@ -0,0 +1 @@
+["a" "b" "c" "d"] unlines w

tests/unlines.msh.stdout

@@ -0,0 +1,4 @@
+a
+b
+c
+d