Add str.lstrip() to compile time

Author: AbdelrahmanKhaledd

src/lpython/semantics/python_ast_to_asr.cpp

@@ -4376,6 +4376,22 @@ 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("lstrip")) {
+                    if(args.size() != 0) {
+                        throw SemanticError("str.lstrip() takes no arguments",
+                            x.base.base.loc);
+                    }
+                    AST::ConstantStr_t *n = AST::down_cast<AST::ConstantStr_t>(at->m_value);
+                    std::string res = n->m_value;
+                    int ind = 0;
+                    while (ind < res.size() && res[ind] == ' ') {
+                        ind++;
+                    }
+                    res = std::string(res.begin() + ind, res.end());
+                    ASR::ttype_t *str_type = ASRUtils::TYPE(ASR::make_Character_t(al, x.base.base.loc,
+                                    1, 1, nullptr, nullptr , 0));
+                    tmp = ASR::make_StringConstant_t(al, x.base.base.loc, s2c(al, res), str_type);
+                    return;
                 } else {
                     throw SemanticError("'str' object has no attribute '" + std::string(at->m_attr) + "'",
                         x.base.base.loc);

src/lpython/semantics/python_comptime_eval.h

@@ -65,6 +65,7 @@ struct PythonIntrinsicProcedures {
             {"_lpython_str_capitalize", {m_builtin, &eval__lpython_str_capitalize}},
             {"_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}},
         };
     }
 
@@ -706,6 +707,22 @@ struct PythonIntrinsicProcedures {
         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_lstrip(Allocator &al, const Location &loc, Vec<ASR::expr_t *> &args) {
+        LFORTRAN_ASSERT(ASRUtils::all_args_evaluated(args));
+        if (args.size() != 0) {
+            throw SemanticError("str.lstrip() takes no arguments", loc);
+        }
+        ASR::expr_t *arg = args[0];
+        ASR::ttype_t *arg_type = ASRUtils::expr_type(arg);
+        std::string res = ASR::down_cast<ASR::StringConstant_t>(arg)->m_s;
+        int ind = 0;
+        while (ind < res.size() && res[ind++] == ' ');
+        res = std::string(res.begin() + ind, res.end());
+        ASR::ttype_t *type = ASRUtils::TYPE(ASR::make_Character_t(al, loc,
+                                    1, 1, nullptr, nullptr, 0));
+        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));
+    }
 
 }; // ComptimeEval