From a0febfba0e91d9c3fcae73c4355118fdd6365af0 Mon Sep 17 00:00:00 2001
From: Stepan Usatiuk <stepan@usatiuk.com>
Date: Tue, 26 Dec 2023 13:41:14 +0100
Subject: [PATCH] even better parser

---
 src/vm/CMakeLists.txt        |  2 +-
 src/vm/includes/SParser.h    | 14 --------------
 src/vm/src/Parser.cpp        | 22 ++++++++++++++++++----
 src/vm/src/SParser.cpp       |  5 -----
 test/vm/VMWithParserTest.cpp |  6 +++---
 5 files changed, 22 insertions(+), 27 deletions(-)
 delete mode 100644 src/vm/includes/SParser.h
 delete mode 100644 src/vm/src/SParser.cpp

diff --git a/src/vm/CMakeLists.txt b/src/vm/CMakeLists.txt
index f7c69d9..067692e 100644
--- a/src/vm/CMakeLists.txt
+++ b/src/vm/CMakeLists.txt
@@ -2,6 +2,6 @@ set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 add_library(vm src/VM.cpp src/Cell.cpp
-        src/Parser.cpp src/SParser.cpp src/MemoryContext.cpp src/ConsUtils.cpp)
+        src/Parser.cpp src/MemoryContext.cpp src/ConsUtils.cpp)
 
 target_include_directories(vm PUBLIC includes)
diff --git a/src/vm/includes/SParser.h b/src/vm/includes/SParser.h
deleted file mode 100644
index e2bdbdb..0000000
--- a/src/vm/includes/SParser.h
+++ /dev/null
@@ -1,14 +0,0 @@
-//
-// Created by Stepan Usatiuk on 25.12.2023.
-//
-
-#ifndef PSIL_SPARSER_H
-#define PSIL_SPARSER_H
-
-
-class SParser {
-    //    SParser()
-};
-
-
-#endif//PSIL_SPARSER_H
diff --git a/src/vm/src/Parser.cpp b/src/vm/src/Parser.cpp
index 16edb4d..2445e84 100644
--- a/src/vm/src/Parser.cpp
+++ b/src/vm/src/Parser.cpp
@@ -4,6 +4,7 @@
 
 #include "Parser.h"
 
+#include <format>
 #include <ranges>
 #include <stack>
 
@@ -62,10 +63,23 @@ std::string_view Parser::Tokenizer::peek() const {
 }
 
 void Parser::Tokenizer::load(std::string_view input) {
-    for (const auto &w: input | std::views::split(' ') | std::views::transform([](auto &&rng) {
-                            return std::string_view(&*rng.begin(), std::ranges::distance(rng));
-                        })) {
-        _tokens.emplace(w);
+    std::string_view::size_type curpos = input.find_first_not_of(' ');
+
+    static const std::string alnum = "-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+    static const std::string special = "().";
+
+    while (curpos != std::string_view::npos) {
+        if (alnum.find(input.at(curpos)) != std::string::npos) {
+            std::string_view::size_type end = input.find_first_not_of(alnum, curpos);
+            _tokens.emplace(input.cbegin() + curpos, input.cbegin() + end);
+            curpos = end;
+        } else if (special.find(input.at(curpos)) != std::string::npos) {
+            _tokens.emplace(1, input.at(curpos));
+            curpos++;
+        } else {
+            throw std::invalid_argument("Unexpected symbol " + std::string(1, input.at(curpos)));
+        }
+        curpos = input.find_first_not_of(' ', curpos);
     }
 }
 
diff --git a/src/vm/src/SParser.cpp b/src/vm/src/SParser.cpp
deleted file mode 100644
index ca55a17..0000000
--- a/src/vm/src/SParser.cpp
+++ /dev/null
@@ -1,5 +0,0 @@
-//
-// Created by Stepan Usatiuk on 25.12.2023.
-//
-
-#include "SParser.h"
diff --git a/test/vm/VMWithParserTest.cpp b/test/vm/VMWithParserTest.cpp
index bdc3837..be5030a 100644
--- a/test/vm/VMWithParserTest.cpp
+++ b/test/vm/VMWithParserTest.cpp
@@ -10,7 +10,7 @@ TEST(VMWithParserTest, BasicHello) {
         MemoryContext mc;
         VM vm(ssin, ssout);
         Parser parser;
-        parser.loadStr("( LDC 104 PUTCHAR STOP )");
+        parser.loadStr("(LDC 104 PUTCHAR STOP)");
         vm.loadControl(parser.parseExpr());
         vm.run();
     }
@@ -26,7 +26,7 @@ TEST(VMWithParserTest, BasicBranch) {
         VM vm(ssin, ssout);
         Parser parser;
         parser.loadStr(
-                "( LDC 1 SEL ( LDC 10 PUTNUM JOIN ) ( LDC 20 PUTNUM JOIN ) LDC 0 SEL ( LDC 30 PUTNUM JOIN ) ( LDC 40 PUTNUM JOIN ) STOP )");
+                "(LDC 1 SEL (LDC 10 PUTNUM JOIN) (LDC 20 PUTNUM JOIN) LDC 0 SEL (LDC 30 PUTNUM JOIN) (LDC 40 PUTNUM JOIN) STOP)");
         vm.loadControl(parser.parseExpr());
         vm.run();
     }
@@ -41,7 +41,7 @@ TEST(VMWithParserTest, BasicFunction) {
         MemoryContext mc;
         VM vm(ssin, ssout);
         Parser parser;
-        parser.loadStr("( NIL LDC 1 CONS LDC 2 CONS LDF ( LD ( 1 . 1 ) LD ( 1 . 2 ) ADD RET ) AP PUTNUM STOP )");
+        parser.loadStr("(NIL LDC 1 CONS LDC 2 CONS LDF (LD (1 . 1) LD (1.2) ADD RET) AP PUTNUM STOP)");
         vm.loadControl(parser.parseExpr());
         vm.run();
     }