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Merged
merged 4 commits into from
Aug 31, 2022
Merged

Strings methods: startswith() #1049

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b3403d7
Add `str.startswith()` to `ast -> asr`
AbdelrahmanKhaledd Aug 30, 2022
156036a
Add `str.startswith()` to `lpython_builtin`
AbdelrahmanKhaledd Aug 30, 2022
d03cd89
Add `str.startswith()` to compile time
AbdelrahmanKhaledd Aug 30, 2022
10fde29
Add tests for `str.startswith()`, Update refs
AbdelrahmanKhaledd Aug 30, 2022
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18 changes: 18 additions & 0 deletions integration_tests/test_str_attributes.py
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,24 @@ def strip():
assert " AASAsaSas " .lstrip() == "AASAsaSas "
assert " AASAsaSas " .strip() == "AASAsaSas"

def startswith():
s: str
s = " empty"
assert s.startswith(" ") == True
assert " @" .startswith(" ") == True
assert " emptyAaaaAABBbbbbBB" .startswith(s) == True
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Let's try giving something in the middle portion of the string such as AABB in startswith and see if it returns False. Also give something like emptyAaaX as input to startswith.

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i added them and edit those corner cases in functions, i think it's ready now.

assert " emptyAaaaAABBbbbbBB" .startswith("AABB") == False
assert " emptyAaaaAABBbbbbBB" .startswith("emptyAaxX") == False

assert "". startswith("sd") == False
assert "empty" .startswith("") == True
assert "".startswith("") == True
assert s.startswith("") == True
s = ""
assert s.startswith("") == True
assert s.startswith("sdd") == False

capitalize()
lower()
strip()
startswith()
69 changes: 69 additions & 0 deletions src/lpython/semantics/python_ast_to_asr.cpp
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Expand Up @@ -4554,6 +4554,30 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
args.push_back(al, arg);
tmp = make_call_helper(al, fn_div, current_scope, args, "_lpython_str_strip", x.base.base.loc);
return;
} else if (std::string(at->m_attr) == std::string("startswith")) {
if(args.size() != 1) {
throw SemanticError("str.startwith() takes one argument",
x.base.base.loc);
}
ASR::expr_t *arg_sub = args[0].m_value;
ASR::ttype_t *arg_sub_type = ASRUtils::expr_type(arg_sub);
if(!ASRUtils::is_character(*arg_sub_type)) {
throw SemanticError("str.startwith() takes one argument of type: str",
x.base.base.loc);
}
ASR::symbol_t *fn_div = resolve_intrinsic_function(x.base.base.loc, "_lpython_str_startswith");
Vec<ASR::call_arg_t> function_args;
function_args.reserve(al, 1);
ASR::call_arg_t str;
str.loc = x.base.base.loc;
str.m_value = se;
ASR::call_arg_t sub;
sub.loc = x.base.base.loc;
sub.m_value = args[0].m_value;
function_args.push_back(al, str);
function_args.push_back(al, sub);
tmp = make_call_helper(al, fn_div, current_scope, function_args, "_lpython_str_startswith", x.base.base.loc);
return;
}
}
handle_attribute(se, at->m_attr, x.base.base.loc, eles);
Expand Down Expand Up @@ -4668,6 +4692,51 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
1, 1, nullptr, nullptr , 0));
tmp = ASR::make_StringConstant_t(al, x.base.base.loc, s2c(al, res), str_type);
return;
} else if (std::string(at->m_attr) == std::string("startswith")) {
if (args.size() != 1) {
throw SemanticError("str.startswith() takes one arguments",
x.base.base.loc);
}
ASR::expr_t *arg = args[0].m_value;
ASR::ttype_t *type = ASRUtils::expr_type(arg);
if (ASRUtils::is_character(*type)) {
AST::ConstantStr_t* str_str_con = AST::down_cast<AST::ConstantStr_t>(at->m_value);
std::string str = str_str_con->m_value;
if (ASRUtils::expr_value(arg) != nullptr) {
ASR::StringConstant_t* sub_str_con = ASR::down_cast<ASR::StringConstant_t>(arg);
std::string sub = sub_str_con->m_s;
size_t ind1 = 0, ind2 = 0;
bool res = !(str.size() == 0 && sub.size());
while ((ind1 < str.size()) && (ind2 < sub.size()) && res) {
res &= str[ind1] == sub[ind2];
ind1++;
ind2++;
}
res &= res? (ind2 == sub.size()): true;
tmp = ASR::make_LogicalConstant_t(al, x.base.base.loc, res, ASRUtils::TYPE(ASR::make_Logical_t(al, x.base.base.loc,
4, nullptr, 0)));
} else {
ASR::symbol_t *fn_div = resolve_intrinsic_function(x.base.base.loc, "_lpython_str_startswith");
Vec<ASR::call_arg_t> args;
args.reserve(al, 1);
ASR::call_arg_t str_arg;
str_arg.loc = x.base.base.loc;
ASR::ttype_t *str_type = ASRUtils::TYPE(ASR::make_Character_t(al, x.base.base.loc,
1, 0, nullptr, nullptr, 0));
str_arg.m_value = ASRUtils::EXPR(
ASR::make_StringConstant_t(al, x.base.base.loc, s2c(al, str), str_type));
ASR::call_arg_t sub_arg;
sub_arg.loc = x.base.base.loc;
sub_arg.m_value = arg;
args.push_back(al, str_arg);
args.push_back(al, sub_arg);
tmp = make_call_helper(al, fn_div, current_scope, args, "_lpython_str_startswith", x.base.base.loc);
}
} else {
throw SemanticError("str.startwith() takes one arguments of type: str",
arg->base.loc);
}
return;
} else {
throw SemanticError("'str' object has no attribute '" + std::string(at->m_attr) + "'",
x.base.base.loc);
Expand Down
11 changes: 10 additions & 1 deletion src/lpython/semantics/python_comptime_eval.h
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Expand Up @@ -66,7 +66,8 @@ struct PythonIntrinsicProcedures {
{"_lpython_str_lower", {m_builtin, &eval__lpython_str_lower}},
{"_lpython_str_rstrip", {m_builtin, &eval__lpython_str_rstrip}},
{"_lpython_str_lstrip", {m_builtin, &eval__lpython_str_lstrip}},
{"_lpython_str_strip", {m_builtin, &eval__lpython_str_strip}}
{"_lpython_str_strip", {m_builtin, &eval__lpython_str_strip}},
{"_lpython_str_startswith", {m_builtin, &eval__lpython_str_startswith}}
};
}

Expand Down Expand Up @@ -740,6 +741,14 @@ struct PythonIntrinsicProcedures {
ASR::ttype_t *res_type = ASRUtils::TYPE(ASR::make_StringConstant_t(al, loc, s2c(al, ""), type));
return ASR::down_cast<ASR::expr_t>(ASR::make_StringConstant_t(al, loc, s2c(al, res), res_type));
}

static ASR::expr_t *eval__lpython_str_startswith(Allocator &al, const Location &loc, Vec<ASR::expr_t *> &/*args*/) {
// compile time action implemented on ast->asr
ASR::ttype_t* res_type = ASRUtils::TYPE(ASR::make_Logical_t(al, loc,
4, nullptr, 0));
return ASR::down_cast<ASR::expr_t>(ASR::make_LogicalConstant_t(al, loc, 0, res_type));
}

}; // ComptimeEval

} // namespace LFortran
Expand Down
13 changes: 13 additions & 0 deletions src/runtime/lpython_builtin.py
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Expand Up @@ -659,3 +659,16 @@ def _lpython_str_strip(x: str) -> str:
res = _lpython_str_lstrip(x)
res = _lpython_str_rstrip(res)
return res

@overload
def _lpython_str_startswith(s: str ,sub: str) -> bool:
res :bool
res = not (len(s) == 0 and len(sub) > 0)
i: i32; j: i32
i = 0; j = 0
while (i < len(s)) and ((j < len(sub)) and res):
res = res and (s[i] == sub[j])
i += 1; j+=1
if res:
res = res and (j == len(sub))
return res
2 changes: 1 addition & 1 deletion tests/reference/asr-complex1-f26c460.json
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
"outfile": null,
"outfile_hash": null,
"stdout": "asr-complex1-f26c460.stdout",
"stdout_hash": "18b20d566cba3464ada1eca0f7570f65ab4ab77e0a957ea2285a5a0b",
"stdout_hash": "533e7e69cb0732f89d58e6ee1d45d246cda1466bad59e039353ec7d3",
"stderr": null,
"stderr_hash": null,
"returncode": 0
Expand Down
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