make it clear when the program doesn't compile

Author: paigeruten

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 1.0.0beta4 (April 8, 2017)
+
+* In the [Multiple lines](http://viewsourcecode.org/snaptoken/kilo/04.aTextViewer.html#multiple-lines)
+  section, make it clearer that the program doesn't compile for those steps.
+  (Thanks @mapleray and @agentultra)
+
 ## 1.0.0beta3 (April 7, 2017)
 
 * In `editorPrompt()`, change `!iscntrl(c)` to `!iscntrl(c) && c < 128`, so

doc/04.aTextViewer.md

@@ -99,7 +99,9 @@ empty.
 
 To store multiple lines, let's make `E.row` an array of `erow` structs. It will
 be a dynamically-allocated array, so we'll make it a pointer to `erow`, and
-initialize the pointer to `NULL`.
+initialize the pointer to `NULL`. (This will break a bunch of our code that
+doesn't expect `E.row` to be a pointer, so the program will fail to compile for
+the next few steps.)
 
 {{erow-array}}
 
@@ -109,6 +111,9 @@ function called `editorAppendRow()`. We'll also put it under a new section,
 
 {{append-row}}
 
+Notice that we renamed the `line` and `linelen` variables to `s` and `len`,
+which are now arguments to `editorAppendRow()`.
+
 We want `editorAppendRow()` to allocate space for a new `erow`, and then copy
 the given string to a new `erow` at the end of the `E.row` array. Let's do that
 now.
@@ -118,9 +123,8 @@ now.
 We have to tell `realloc()` how many bytes we want to allocate, so we multiply
 the number of bytes each `erow` takes (`sizeof(erow)`) and multiply that by the
 number of rows we want. Then we set `at` to the index of the new row we want to
-initialize, and replace each occurrence of `E.row` with `E.row[at]`. We also
-make sure to use the argument names `s` and `len` instead of `line` and
-`linelen`. Lastly, we change `E.numrows = 1` to `E.numrows++`.
+initialize, and replace each occurrence of `E.row` with `E.row[at]`. Lastly, we
+change `E.numrows = 1` to `E.numrows++`.
 
 Next, let's update `editorDrawRows()` to use `E.row[y]` instead of `E.row`,
 when printing out the current line.

leg.yml

@@ -1,6 +1,6 @@
 ---
 :name: kilo
-:version: "1.0.0beta3"
+:version: "1.0.0beta4"
 :title: Build Your Own Text Editor
 :rouge_theme: github
 :bold_weight: 500

steps.diff

@@ -1606,10 +1606,10 @@ diff --git a/kilo.c b/kilo.c
 +/*** row operations ***/
 +
 +void editorAppendRow(char *s, size_t len) {
-+  E.row.size = linelen;
-+  E.row.chars = malloc(linelen + 1);
-+  memcpy(E.row.chars, line, linelen);
-+  E.row.chars[linelen] = '\0';
++  E.row.size = len;
++  E.row.chars = malloc(len + 1);
++  memcpy(E.row.chars, s, len);
++  E.row.chars[len] = '\0';
 +  E.numrows = 1;
 +}
 +
@@ -1638,10 +1638,10 @@ diff --git a/kilo.c b/kilo.c
  /*** row operations ***/
 
  void editorAppendRow(char *s, size_t len) {
--  E.row.size = linelen;
--  E.row.chars = malloc(linelen + 1);
--  memcpy(E.row.chars, line, linelen);
--  E.row.chars[linelen] = '\0';
+-  E.row.size = len;
+-  E.row.chars = malloc(len + 1);
+-  memcpy(E.row.chars, s, len);
+-  E.row.chars[len] = '\0';
 -  E.numrows = 1;
 +  E.row = realloc(E.row, sizeof(erow) * (E.numrows + 1));
 +