Tidy up

docs/lectures/compilers/01_structures.md

@@ -1,6 +1,6 @@
 # Compilers - COMP 3012
 
-A compiler is a tool that maps one language into another language. It takes a program written in a source programming language and maps it to program written in a target programming language. A compiler is written in an **implementation language**.
+A compiler is a tool that maps one language into another language. It takes a program written in a source programming language and maps it to a program written in a target programming language. A compiler is written in an **implementation language**.
 
 ![img](img/a.png)
 
@@ -10,21 +10,21 @@ An **interpreter** is a program that takes a source program and executes the pro
 
 ![img](img/b.png)
 
-> NOTE: Java uses both. A java source program is compiled into byte code (by a compiler) which is then executed by an interpreter (called java virtual machine - JVM). JVM will also compile fragments of code so that if there is a call back, it can execute the compiled code. This is called compilation on the fly.
+> NOTE: Java uses both. A Java source program is compiled into bytecode (by a compiler), which is then executed by an interpreter (called the Java virtual machine - JVM). The JVM will also compile fragments of code so that if there is a call back, it can execute the compiled code. This is called compilation on the fly.
 
-Compilers will often use an **intermediate representation (IR)** to bridge the gap between the source language and the executable language. Converting source language to IR is called **front end**, where as converting IR to executable code is called **back end**.
+Compilers will often use an **intermediate representation (IR)** to bridge the gap between the source language and the executable language. Converting source language to IR is called **front end**, whereas converting IR to executable code is called **back end**.
 
-* The front end focuses on understand the source-language program. 
-* The back end focuses on mapping programs to the target machine
+- The front end focuses on understanding the source-language program.
+- The back end focuses on mapping programs to the target machine
 
 ![img](img/c.png)
 
-* The front end, intermediate representation and the back end are all part of the compiler.
+- The front end, intermediate representation and the back end are all part of the compiler.
 
 IR is stored as an Abstract Syntax Tree **AST**.
 
 The syntactic details needed for parsing the source program are represented in the structure of the tree.
 
-The **IR** could be broken down into many sub-steps i.e. a IR1 could be created which is then ran through an optimiser to create IR2 which is fed into the back end instead of IR1. This is called a *three-phase compiler*.
+The **IR** could be broken down into many sub-steps, i.e. an IR1 could be created, which is then run through an optimiser to create IR2, which is fed into the back end instead of IR1. This is called a *three-phase compiler*.
 
-![img](img/d.png)
+![img](img/d.png)