From a0f0c005a39ddaf693c7de84d6ab1c380a93dca2 Mon Sep 17 00:00:00 2001
From: Adrian Kummerländer
Date: Thu, 26 Sep 2013 20:41:37 +0200
Subject: Code restructuring of tree and parsing logic * Enabled tree to
 generate itself ** Main work is now done during tree construction * Moved
 lexer and getPriority utility functions into separate compilation unit

---
 src/utils.cc | 115 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 src/utils.cc

(limited to 'src/utils.cc')

diff --git a/src/utils.cc b/src/utils.cc
new file mode 100644
index 0000000..7457ae2
--- /dev/null
+++ b/src/utils.cc
@@ -0,0 +1,115 @@
+#include "utils.h"
+#include "exceptions.h"
+
+#include "tree.h"
+
+namespace SimpleParser {
+
+int8_t getPriority(char tmp) {
+	switch ( tmp ) {
+		case '-':
+			return 10;
+		case '+':
+			return 10;
+		case '/':
+			return 20;
+		case '*':
+			return 20;
+		case '^':
+			return 30;
+		case '(':
+			return 90;
+		case ')':
+			return 90;
+		case ',':
+			return -1;
+		default:
+			return -1;
+	}
+}
+
+std::vector<std::string> lexer(std::string term) {
+	std::string tmp;
+	std::string tmpNum;
+	std::vector<std::string> output;
+
+	int8_t   priority     = 0;
+	int8_t   lastPriority = 0;
+	uint32_t level        = 0;
+
+	for ( auto termIter = term.begin();
+	      termIter     != term.end();
+	      termIter++ ) {
+		priority = getPriority(*termIter);
+
+		if ( priority == -1 || ( termIter == term.begin() &&
+		                         priority == 10 ) ) {
+			if ( level > 0 ) {
+				tmp += *termIter;
+			} else {
+				tmpNum += *termIter;
+			}
+		} else {
+			if ( lastPriority == -1 && level == 0 ) {
+				output.push_back(tmpNum);
+				tmpNum.clear();
+			}
+
+			switch ( *termIter ) {
+				case '(': {
+					if ( level > 0 ) {
+						tmp += *termIter;
+					}
+
+					level++;
+
+					break;
+				}
+				case ')': {
+					level--;
+
+					if ( level == 0 ) {
+						output.push_back(tmp);
+						tmp.clear();
+					} else {
+						tmp += *termIter;
+					}
+
+					break;
+				}
+				default: {
+					if ( level == 0 ) {
+						std::string helper;
+						helper = *termIter;
+
+						output.push_back(helper);
+					} else {
+						tmp += *termIter;
+					}
+
+					break;
+				}
+			}
+		}
+
+		lastPriority = priority;
+	}
+
+	if ( lastPriority == -1 ) {
+		output.push_back(tmpNum);
+	} else if ( lastPriority != 90 ) {
+		throw operator_exception();
+	}
+
+	if (level != 0) {
+		throw parenthese_exception();
+	}
+
+	if ( lastPriority == 90 && output.size() == 1 ) {
+		output = lexer(output[0]);
+	}
+
+	return output;
+}
+
+}
-- 
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