Changes

The parse graphs that we've been looking at so far bring us one step closer to the pointer graphs that it takes to make these trees live in computer memory, but they are still a couple of steps too abstract to detail the concrete species of dynamic data structures that we need.  The time has come to flesh out the skeleton that we've drawn up to this point.

The parse graphs that we've been looking at so far bring us one step closer to the pointer graphs that it takes to make these trees live in computer memory, but they are still a couple of steps too abstract to detail the concrete species of dynamic data structures that we need.  The time has come to flesh out the skeleton that we've drawn up to this point.

Nodes in a graph represent ''records'' in computer memory.  A record is a collection of data that can be conceived to reside at a specific ''address''.  The address of a record is commonly described by programmers, on analogy with demonstrative pronouns, as a ''pointer'', and semioticians recognize it as a type of sign called an ''index''.

Nodes in a graph represent ''records'' in computer memory.  A record is a collection of data that can be conceived to reside at a specific ''address''.  Because the address of a record is analogous to a demonstrative pronoun like ''this'' or ''that'' programmers commonly describe it as a ''pointer'' and semioticians recognize it as a type of sign called an ''index''.

At the next level of concreteness, a record-node can be represented as follows:

At the next level of concreteness, a pointer→record data compound can be represented as follows:

<pre>

<p>[[Image:Logical_Graph_Figure_11.jpg|center]]</p>

          | datum_1 datum_2 datum_3 ... |                   

          |                                                

</pre>

This depicts the circumstance that index₀ is the address of the record in question, which record contains the following data:

This portrays <math>index_0\!</math> as the address of a record that contains the data, <math>datum_1,\!</math> <math>datum_2,\!</math> <math>datum_3, \ldots,\!</math> and so on.

 

::: datum₁, datum₂, datum₃, ..., and so on.

What makes it possible to represent graph-theoretical structures as data structures in computer memory is the fact that an address is just another datum, and so we can have a circumstance like this:

What makes it possible to represent graph-theoretical structures as data structures in computer memory is the fact that an address is just another datum, and so we can have a circumstance like this: