pycep.analyzer Module

pycep.analyzer.parse(source)

The analyzer takes a string containing the source code as an input and returns an abstract syntax tree.

>>> import pycep.analyzer
>>> import ast
>>> tree = pycep.analyzer.parse('print "Hello, world!"')
>>> ast.dump(tree)
"Module(body=[Print(dest=None, values=[Str(s='Hello, world!')], nl=True)])"

Parameters:source (string) – Source code Returns:Abstract Syntax Tree Return type:ast.AST Raises:SyntaxError – Syntax Error

Abstract Syntax Tree of Hello World Example:

See also

• Python Abstract Grammar: https://docs.python.org/2/library/ast.html
• Green Tree Snakes - the missing Python AST docs: https://greentreesnakes.readthedocs.org/

class pycep.analyzer.Analyzer

Convert a parse tree into an abstract syntax tree.

See also

• Visitor Design Pattern https://sourcemaking.com/design_patterns/visitor

visit_single_input(values, ctx)

single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE

visit_file_input(values, ctx)

file_input: (NEWLINE | stmt)* ENDMARKER

visit_eval_input(values, ctx)

eval_input: testlist NEWLINE* ENDMARKER

visit_decorator(values, ctx)

decorator: ‘@’ dotted_name [ ‘(‘ [arglist] ‘)’ ] NEWLINE

visit_decorators(values, ctx)

decorators: decorator+

visit_decorated(values, ctx)

decorated: decorators (classdef | funcdef)

visit_funcdef(values, ctx)

funcdef: ‘def’ NAME parameters ‘:’ suite

visit_parameters(values, ctx)

parameters: ‘(‘ [varargslist] ‘)’

visit_varargslist(values, ctx)

varargslist: ((fpdef [‘=’ test] ‘,’)* (‘*’ NAME [‘,’ ‘**’ NAME] | ‘**’ NAME) | fpdef [‘=’ test] (‘,’ fpdef [‘=’ test])* [‘,’])

visit_fpdef(values, ctx)

fpdef: NAME | ‘(‘ fplist ‘)’

visit_fplist(values, ctx)

fplist: fpdef (‘,’ fpdef)* [‘,’]

visit_stmt(values, ctx)

stmt: simple_stmt | compound_stmt

visit_simple_stmt(values, ctx)

simple_stmt: small_stmt (‘;’ small_stmt)* [‘;’] NEWLINE

visit_small_stmt(values, ctx)

small_stmt: (expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | import_stmt | global_stmt | exec_stmt | assert_stmt)

visit_expr_stmt(values, ctx)

expr_stmt: testlist (augassign (yield_expr|testlist) | (‘=’ (yield_expr|testlist))*)

visit_augassign(values, ctx)

augassign: (‘+=’ | ‘-=’ | ‘*=’ | ‘/=’ | ‘%=’ | ‘&=’ | ‘|=’ | ‘^=’ | ‘<<=’ | ‘>>=’ | ‘**=’ | ‘//=’)

visit_print_stmt(values, ctx)

print_stmt: ‘print’ ( [ test (‘,’ test)* [‘,’] ] | ‘>>’ test [ (‘,’ test)+ [‘,’] ] )

visit_del_stmt(values, ctx)

del_stmt: ‘del’ exprlist

visit_pass_stmt(values, ctx)

pass_stmt: ‘pass’

visit_flow_stmt(values, ctx)

flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt

visit_break_stmt(values, ctx)

break_stmt: ‘break’

visit_continue_stmt(values, ctx)

continue_stmt: ‘continue’

visit_return_stmt(values, ctx)

return_stmt: ‘return’ [testlist]

visit_yield_stmt(values, ctx)

yield_stmt: yield_expr

visit_raise_stmt(values, ctx)

raise_stmt: ‘raise’ [test [‘,’ test [‘,’ test]]]

visit_import_stmt(values, ctx)

import_stmt: import_name | import_from

visit_import_name(values, ctx)

import_name: ‘import’ dotted_as_names

visit_import_from(values, ctx)

import_from: (‘from’ (‘.’* dotted_name | ‘.’+) ‘import’ (‘*’ | ‘(‘ import_as_names ‘)’ | import_as_names))

visit_import_as_name(values, ctx)

import_as_name: NAME [‘as’ NAME]

visit_dotted_as_name(values, ctx)

dotted_as_name: dotted_name [‘as’ NAME]

visit_import_as_names(values, ctx)

import_as_names: import_as_name (‘,’ import_as_name)* [‘,’]

visit_dotted_as_names(values, ctx)

dotted_as_names: dotted_as_name (‘,’ dotted_as_name)*

visit_dotted_name(values, ctx)

dotted_name: NAME (‘.’ NAME)*

visit_global_stmt(values, ctx)

global_stmt: ‘global’ NAME (‘,’ NAME)*

visit_exec_stmt(values, ctx)

exec_stmt: ‘exec’ expr [‘in’ test [‘,’ test]]

visit_assert_stmt(values, ctx)

assert_stmt: ‘assert’ test [‘,’ test]

visit_compound_stmt(values, ctx)

compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated

visit_if_stmt(values, ctx)

if_stmt: ‘if’ test ‘:’ suite (‘elif’ test ‘:’ suite)* [‘else’ ‘:’ suite]

visit_while_stmt(values, ctx)

while_stmt: ‘while’ test ‘:’ suite [‘else’ ‘:’ suite]

visit_for_stmt(values, ctx)

for_stmt: ‘for’ exprlist ‘in’ testlist ‘:’ suite [‘else’ ‘:’ suite]

visit_try_stmt(values, ctx)

try_stmt: (‘try’ ‘:’ suite ((except_clause ‘:’ suite)+

[‘else’ ‘:’ suite] [‘finally’ ‘:’ suite] |

‘finally’ ‘:’ suite))

visit_with_stmt(values, ctx)

with_stmt: ‘with’ with_item (‘,’ with_item)* ‘:’ suite

visit_with_item(values, ctx)

with_item: test [‘as’ expr]

visit_except_clause(values, ctx)

except_clause: ‘except’ [test [(‘as’ | ‘,’) test]]

visit_suite(values, ctx)

suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT

visit_testlist_safe(values, ctx)

testlist_safe: old_test [(‘,’ old_test)+ [‘,’]]

visit_old_test(values, ctx)

old_test: or_test | old_lambdef

visit_old_lambdef(values, ctx)

old_lambdef: ‘lambda’ [varargslist] ‘:’ old_test

visit_test(values, ctx)

test: or_test [‘if’ or_test ‘else’ test] | lambdef

visit_or_test(values, ctx)

or_test: and_test (‘or’ and_test)*

visit_and_test(values, ctx)

and_test: not_test (‘and’ not_test)*

visit_not_test(values, ctx)

not_test: ‘not’ not_test | comparison

visit_comparison(values, ctx)

comparison: expr (comp_op expr)*

visit_comp_op(values, ctx)

comp_op: ‘<’|’>’|’==’|’>=’|’<=’|’<>’|’!=’|’in’|’not’ ‘in’|’is’|’is’ ‘not’

visit_expr(values, ctx)

expr: xor_expr (‘|’ xor_expr)*

visit_xor_expr(values, ctx)

xor_expr: and_expr (‘^’ and_expr)*

visit_and_expr(values, ctx)

and_expr: shift_expr (‘&’ shift_expr)*

visit_shift_expr(values, ctx)

shift_expr: arith_expr ((‘<<’|’>>’) arith_expr)*

visit_arith_expr(values, ctx)

arith_expr: term ((‘+’|’-‘) term)*

visit_term(values, ctx)

term: factor ((‘*’|’/’|’%’|’//’) factor)*

visit_factor(values, ctx)

factor: (‘+’|’-‘|’~’) factor | power

visit_power(values, ctx)

power: atom trailer* [‘**’ factor]

visit_atom(values, ctx)

atom: (‘(‘ [yield_expr|testlist_comp] ‘)’ | ‘[‘ [listmaker] ‘]’ | ‘{‘ [dictorsetmaker] ‘}’ | ‘`’ testlist1 ‘`’ | NAME | NUMBER | STRING+)

visit_listmaker(values, ctx)

listmaker: test ( list_for | (‘,’ test)* [‘,’] )

visit_testlist_comp(values, ctx)

testlist_comp: test ( comp_for | (‘,’ test)* [‘,’] )

visit_lambdef(values, ctx)

lambdef: ‘lambda’ [varargslist] ‘:’ test

visit_trailer(values, ctx)

trailer: ‘(‘ [arglist] ‘)’ | ‘[‘ subscriptlist ‘]’ | ‘.’ NAME

visit_subscriptlist(values, ctx)

subscriptlist: subscript (‘,’ subscript)* [‘,’]

visit_subscript(values, ctx)

subscript: ‘.’ ‘.’ ‘.’ | test | [test] ‘:’ [test] [sliceop]

visit_sliceop(values, ctx)

sliceop: ‘:’ [test]

visit_exprlist(values, ctx)

exprlist: expr (‘,’ expr)* [‘,’]

visit_testlist(values, ctx)

testlist: test (‘,’ test)* [‘,’]

visit_dictorsetmaker(values, ctx)

dictorsetmaker: ( (test ‘:’ test (comp_for | (‘,’ test ‘:’ test)* [‘,’])) | (test (comp_for | (‘,’ test)* [‘,’])) )

visit_classdef(values, ctx)

classdef: ‘class’ NAME [‘(‘ [testlist] ‘)’] ‘:’ suite

visit_arglist(values, ctx)

arglist: (argument ‘,’)* (argument [‘,’] |’*’ test (‘,’ argument)* [‘,’ ‘**’ test] |’**’ test)

visit_argument(values, ctx)

argument: test [comp_for] | test ‘=’ test

visit_list_iter(values, ctx)

list_iter: list_for | list_if

visit_list_for(values, ctx)

list_for: ‘for’ exprlist ‘in’ testlist_safe [list_iter]

visit_list_if(values, ctx)

list_if: ‘if’ old_test [list_iter]

visit_comp_iter(values, ctx)

comp_iter: comp_for | comp_if

visit_comp_for(values, ctx)

comp_for: ‘for’ exprlist ‘in’ or_test [comp_iter]

visit_testlist1(values, ctx)

testlist1: test (‘,’ test)*

visit_encoding_decl(values, ctx)

encoding_decl: NAME

visit_yield_expr(values, ctx)

yield_expr: ‘yield’ [testlist]

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