compilerdesign 1.0.2

A teaching Python library for compiler-design topics: lexer, grammar transforms, FIRST/FOLLOW, LL(1), shift-reduce, LR(0), symbol table, 3AC, DAG, and expression conversion.

compilerdesign

A teaching Python library that covers the entire Compiler Design syllabus in one import. Every function returns a plain dict / str, and every function has a matching show_* pretty-printer so you can read the output at a glance.

pip install compilerdesign

import compilerdesign as cd

cd.show_lexical(cd.lexical_analyzer("int x = 10;"))

Full walkthrough with input formats, outputs and end-to-end examples lives in DOCUMENTATION.md. Version history: CHANGES.md.

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What's inside

Topic	Core function	Pretty-printer
Lexical analysis	lexical_analyzer	show_lexical
Symbol table	build_symbol_table	show_symbol_table
Left-recursion elimination	eliminate_left_recursion	show_grammar
Left factoring	left_factoring	show_grammar
Ambiguity check (heuristic)	check_ambiguity	show_ambiguity
FIRST / FOLLOW	compute_first_follow	show_first_follow
LEADING / TRAILING	compute_leading_trailing	show_leading_trailing
LL(1) table + parse trace	build_ll1_table / ll1_parse	show_ll1_table / show_parse_trace
Shift-reduce parser	shift_reduce_parse	show_parse_trace
LR(0) canonical collection	compute_lr0_items	show_lr0
Infix ↔ Postfix ↔ Prefix	convert_expression, etc.	show_expression
Three-address code (quadruples)	generate_three_address_code	show_three_address_code
DAG of an expression	build_dag	show_dag

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60-second tour

import compilerdesign as cd

# 1) Lexical + Symbol table
src = """
int add(int a, int b) {
    int c = a + b * 2;
    return c;
}
"""
cd.show_lexical(cd.lexical_analyzer(src))
cd.show_symbol_table(cd.build_symbol_table(src))

# 2) Expression → 3AC → DAG
expr = "a + b * c - d"
cd.show_three_address_code(cd.generate_three_address_code(expr))
cd.show_dag(cd.build_dag(expr))

# 3) Grammar pipeline
g = {'E': ['E + T', 'T'], 'T': ['T * F', 'F'], 'F': ['( E )', 'id']}
g = cd.eliminate_left_recursion(g)
cd.show_grammar(g, "NO LEFT RECURSION")
cd.show_first_follow(cd.compute_first_follow(g, start='E'))
cd.show_ll1_table(cd.build_ll1_table(g, start='E'))
cd.show_parse_trace(
    cd.ll1_parse(g, ['id', '+', 'id', '*', 'id'], start='E'),
    "LL(1) PARSE",
)

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Grammar input format

grammar = {
    'E': ['E + T', 'T'],    # each production is a space-separated string
    'T': ['T * F', 'F'],
    'F': ['( E )', 'id'],
}
# epsilon: 'ε' or 'eps'

Shift-reduce / LR(0) take a list of tuples instead:

productions = [
    ('E', ['E', '+', 'T']),
    ('E', ['T']),
    ('T', ['id']),
]

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Running tests

python test_all.py

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License

MIT — see DOCUMENTATION.md for the full reference.