This PPT helps you to study about Toy Interpreter and also uses it to make a presentation about this topic.

1. WELCOME
Name: Dhrumil I. Panchal
Enrollment No.: 170410107053
Subject: System Programming
Branch: Computer Engineering
Sem: 5th Sem
Year: 2019-20

2. Topic
Toy Interpreter

3. Contain
 Interpreter
 Toy Interpreter
 Interpreter Data Structure

4. Interpreter
 An interpreter is system software that translates a
given High-Level Language (HLL) program into a
low-level one, but it differs from compilers.
 Interpretation is a real-time activity where an
interpreter takes the program, one statement at a
time, and translates each line before executing it.

5. Toy Interpreter
 It is language processor that bridges execution
gap of a program without generating a target
program.
 The interpreter is itself a program in a
programming language , which is compiled by a
compiler of that language.
 The interpreter uses the symbol table and the
data stores are as follows: The symbol table has
entries for all the variables used in the program .
Each entry holds the name , type and address of
the variable.

6. Toy Interpreter
 The data store that holds values of all program
variables and partial results during interpretation.
 It consists of two large arrays named rvar and ivar
which are used to store values of types real and
integer respectively.
 Last few locations in the array rvar and ivar are
used to stacks for expression evaluation with the
help of pointers r_tos and i_ios respectively. The
stack grows upward in the array.

7. Toy Interpreter
 Each entry in the symbol table is a variable of
type symmetry. The type field of the entry is a
variable of enumerated type which takes either
real_type or int_type as its values.

8. Toy Interpreter
 The interpreter program contains a set of routines
for use in expression evaluations one routine for
each kind of legal sub expression.
real a, b
integer c
let c=7
let b=1.2
a = b + c

9. Toy Interpreter
 It implements the meaning by invoking
appropriate routines.
 ivar[5] :=7
 Similarly rvar[13] :=1.2
 For interpretation of a=b+c procedure add is
called with the symbol table entries of b and c.
 add analyzes the type of b and c and decides that
procedure addrealint will have to be called to
realize the addition.

10. Toy Interpreter
 Addrealint executes rvar[r_tos] :=rvar[13] +
ivar[5];
 So while compiling the expression rvar[addr1] +
ivar[addr2]
 Thus , the interpreter simply arranges to execute
this statement under the right conditions.

11. Interpreter Data Structure
Symbol Type Address
a real 8
b real 13
c int 5
rvar
a
b
ivar
c
Symbol Table
8
13
r_tos
5
i_tos

12. References
 Inspiration from Prof. Shrina Patel and Prof. Rimi
Gupta
 Notes of SP
 System Programming By D M Dhamdhere
 Images from Google Images
 Some My Own Knowledge

13. Thank You