C_Interpreter
This started as C port of an old college assignment in C++. You can see that in the first commit though I might have made some minor changes/improvements during port.
Now my goal is to make something approaching scriptable C. I'll consider it done when it can run itself ... so it'll probably never be completely done.
Download
Get the source from Github.
Alternatives
If you're looking for something more professional there's
- Cling
-
TCC, a compiler that's so fast and self-contained they have a command line switch -run to immediately run it after compiling so you can use C as a JIT scripting language,
Tests
I've kept the old tests around (updating them so they keep working) but I've been adding new tests for new features. They're not comprehensive and they don't test every edge case but they're growing.
Misc
I'm using the 5th edition of C: A Reference Manual for all the nitty gritty details and the very convenient complete C grammar/syntax in the appendix.
I've also added a BNF spec for C I found online just to have something for reference in the repository.
Current Grammar (work in progress)
Preprocessor
#include "relative path based on current directory"
#define name
#define name sequence_of_tokens
#define name ( identifier-list ) sequence_of_tokens
#undef name
# (null directive)
It also of course supports actually using the macros.
C language
translation_unit -> top_level_declaration
translation_unit top_level_declaration
declaration_list -> declaration
function_definition
function_definition -> declaration_specifier function_declarator compound_statement
function_declarator -> identifier '(' parameter_list ')'
parameter_list -> parameter_declaration
parameter_list ',' paramater_declaration
parameter_declaration -> declaration_specifier identifier
declaration -> declaration_specifier initialized_declarator_list ';'
initialized_declarator_list -> initialized_declarator
initialized_declarator_list ',' initialized_declarator
initialized_declarator -> identifier
identifier '=' assign_expr
declaration_specifier -> char, signed char
short, short int, signed short, signed short int
int, signed int, signed
long, long int, signed long, signed long int
unsigned char
unsigned short, unsigned short int
unsigned, unsigned int
unsigned long, unsigned long int
float
double
compound_statement -> '{' decl_or_stmt_list '}'
decl_or_stmt_list -> decl_or_stmt
decl_or_stmt_list decl_or_stmt
decl_or_stmt -> declaration
statement
statement -> expr_stmt
while_stmt
for_stmt
do_stmt
if_stmt
print_stmt
compound_statement
return_stmt
goto_stmt
labeled_stmt
break_or_continue_stmt
switch_stmt
case_or_default_stmt
null_stmt
null_stmt -> ';'
switch_stmt -> switch '(' expr ')' statement
case_or_default_stmt -> case constant_expr ':'
default ':'
constant_expr -> cond_expr //nothing but integer literals allowed
//see tests/switch.c
break_or_continue_stmt -> break ';'
continue ';'
labeled_stmt -> identifier ':' statement
do_stmt -> do statement while '(' expr ')' ';'
while_stmt -> while '(' expr ')' statement
for_stmt -> for for_expressions statement
for_expressions -> '(' initial_clause<opt> ';' expr<opt> ';' expr<opt> ')'
initial_clause -> expr
declaration
if_stmt -> if '(' expr ')' statement
if '(' expr ')' statement else statement
print_stmt -> print expr ';'
goto_stmt -> goto identifier ';'
expr_stmt -> expr ';'
expr -> comma_expr
comma_expr -> assign_expr
assign_expr ',' assign_expr
assign_expr -> cond_expr
identifier assign_op assign_expr
assign_op -> one of '=' '+=' '-=' '*=' '/=' '%='
cond_expr -> logical_or_expr
logica_or_expr '?' expr ':' cond_expr
logical_or_expr -> logical_and_expr
logical_or_expr '||' logical_and_expr
logical_and_expr -> bit_or_expr
logical_and_expr '&&' bit_or_expr
bit_or_expr -> bit_xor_expr
bit_or_expr '|' bit_xor_expr
bit_xor_expr -> bit_and_expr
bit_xor_expr '^' bit_and_expr
bit_and_expr -> equality_expr
bit_and_expr '&' equality_expr
equality_expr -> relational_expr
equality_expr '==' relational_expr
equality_expr '!=' relational_expr
relational_expr -> shift_expr
relational_expr relational_op shift_expr
relational_op -> one of '<' '>' '<=' '>='
shift_expr -> add_expr
shift_expr '<<' add_expr
shift_expr '>>' add_expr
add_expr -> mult_expr
add_expr '+' mult_expr
add_expr '-' mult_expr
mult_expr -> unary_expr
mult_expr mult_op unary_expr
mult_op -> one of '*' '/' '%'
unary_expr -> postfix_expr
bit_negation_expr
logical_negation_expr
preincrement_expr
predecrement_expr
preincrement_expr -> '++' unary_expr
predecrement_expr -> '--' unary_expr
logical_negation_expr -> '!' unary_expr
bit_negation_expr -> '~' unary_expr
postfix_expr -> function_call
primary_expr
postincrement_expr
postdecrement_expr
postincrement_expr -> postfix_expr '++'
postdecrement_expr -> postfix_expr '--'
function_call -> identifier '(' expression_list ')'
expression_list -> assign_expr
expression_list ',' assign_expr
primary_expr -> identifier
constant
'(' expr ')'
Building and Running
I use premake for generating makefiles and have shell scripts for running all my tests at once.
~ $ git clone https://github.com/rswinkle/C_Interpreter.git
Cloning into 'C_Interpreter'...
remote: Reusing existing pack: 489, done.
remote: Total 489 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (489/489), 168.87 KiB | 301.00 KiB/s, done.
Resolving deltas: 100% (264/264), done.
Checking connectivity... done.
~ $ cd C_Interpreter/
~/C_Interpreter $ premake4 gmake
Building configurations...
Running action 'gmake'...
Generating build/Makefile...
Generating build/cinterpreter.make...
Done.
~/C_Interpreter $ cd build/
~/C_Interpreter/build $ make
==== Building cinterpreter (debug) ====
...
Linking cinterpreter
~/C_Interpreter/build $ ./cinterpreter
Usage: ./cinterpreter [-E] script
~/C_Interpreter/build $ ./cinterpreter ../tests/switch.txt
[ouhput from switch.txt here]
~/C_Interpreter/build $ ../runtests.sh
running normal tests
==================
executing ../tests/backslash.txt
executing ../tests/break_continue.txt
executing ../tests/problem6.txt
...
comparing output of ../tests/backslash.txt
comparing output of ../tests/break_continue.txt
comparing output of ../tests/problem6.txt
...
~/C_Interpreter/build $ ../runtests_valgrind.sh | grep ERROR
==30652== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
==30652== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
==30655== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
...
~/C_Interpreter/build $
