operations: implement "l" cmd

README.md

@@ -151,8 +151,7 @@ Files generated.c and - are identical
 
 # Notes
 
-- Missing commands (supporting those is planned):
-  - l
+- Missing command (supporting it is planned):
   - w
 
 - Missing/incomplete features (supporting those is planned):

operations.c

@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <ctype.h>
 #include <regex.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -257,6 +258,60 @@ operation_ret n(Status *const status) {
   return 0;
 }
 
+void l(const Status *const status) {
+  const char *const pattern_space = status->pattern_space;
+  for (int i = 0, fold_counter = 0; pattern_space[i]; ++i, ++fold_counter) {
+    const char c = pattern_space[i];
+    if (fold_counter > 80) {
+      puts("\\");
+      fold_counter = 0;
+    }
+    if (isprint(c)) {
+      if (c == '\\') { // needs to be doubled
+        putchar('\\');
+        fold_counter++;
+      }
+      putchar(c);
+    } else {
+      fold_counter++;
+      switch (c) {
+        case '\n':
+          // POSIX states:
+          // > [...] '\t', '\v' ) shall be written as the corresponding escape
+          // > sequence; the '\n' in that table is not applicable
+          //
+          // toybox and gnu sed still print newlines as "\n", I'll choose to
+          // stick to my understanding of POSIX there.
+          puts("$");
+          fold_counter = 0;
+        case '\a':
+          printf("\\a");
+          break;
+        case '\b':
+          printf("\\b");
+          break;
+        case '\f':
+          printf("\\f");
+          break;
+        case '\r':
+          printf("\\r");
+          break;
+        case '\t':
+          printf("\\t");
+          break;
+        case '\v':
+          printf("\\v");
+          break;
+        default:
+          fold_counter += 2; // 3 counting the beginning of the else branch
+          printf("\\%03hho", c);
+          break;
+      }
+    }
+  }
+  puts("$");
+}
+
 operation_ret N(Status *const status) {
   char *const pattern_space = status->pattern_space;
   const int pattern_space_len = strlen(pattern_space);

operations.h

@@ -18,6 +18,7 @@ void G(Status *const status);
 void h(Status *const status);
 void H(Status *const status);
 void i(const char *const output);
+void l(const Status *const status);
 operation_ret n(Status *const status);
 operation_ret N(Status *const status);
 void p(const Status *const status);

par.sed

@@ -65,8 +65,8 @@ t single_char_cmd
 
 s/^\([aci]\)[[:blank:]]*\\$/\1/; t aci_cmds
 
-# TODO missing cmds
-# w, l
+# TODO missing cmd
+# w
 
 : address_check
 s|^/|&|; t addr_regex

test

@@ -414,6 +414,8 @@ verify 'N; y/a\nb/dxe/' 'Hello
 World'
 verify 'y///' 'foo'
 
+verify 'l' 'foo \\ \ '"$(printf '\a\b\f\r\t\v')"' é '"$(printf '\001\020\300')"' bar'
+
 verify 'r non-existing-file
 s/^/x/' 'bar
 baz'