adding documentation for draw_data and list() (#350)

doc/README_2.md

@@ -40,7 +40,7 @@ a learning environment that uses SICP JS and Source, comes with the following
 ## What can you do in Source §2?
 
 You can use all features of
-<a href="../Source §1/">Source §1</a> and all
+<a href="../source_1/">Source §1</a> and all
 features that are introduced in
 <a href="https://sicp.comp.nus.edu.sg/chapters/23">chapter 2</a> of the
 textbook.

doc/README_3.md

@@ -46,7 +46,7 @@ a learning environment that uses SICP JS and Source, comes with the following
 ## What can you do in Source §3?
 
 You can use all features of
-<a href="../Source §2/">Source §2</a> and all
+<a href="../source_2/">Source §2</a> and all
 features that are introduced in
 <a href="https://sicp.comp.nus.edu.sg/chapters/47">chapter 3</a> of the
 textbook.

doc/list.js

@@ -54,6 +54,24 @@ function is_list(xs) {
     return is_null(xs) || (is_pair(xs) && is_list(tail(xs)));
 }
 
+/**
+ * Given <CODE>n</CODE> values, returns a list of length <CODE>n</CODE>.
+ * The elements of the list are the given values in the given order.
+ * @param {number} value1,value2,...,value_n - given values
+ * @returns {list} list containing all values
+ */
+function list(value1, value2, ...values ) {}
+
+/**
+ * visualizes <CODE>x</CODE> in a separate drawing
+ * area in the Source Academy using a box-and-pointer diagram; time, space:
+ * O(n), where n is the number of data structures such as
+ * pairs in <CODE>x</CODE>.
+ * @param {value} x - given value
+ * @returns {value} given <CODE>x</CODE>
+ */
+function draw_data(x) {}
+
 /**
  * Returns <CODE>true</CODE> if both
  * have the same structure with respect to <CODE>pair</CODE>,