From 7e6ab875c962b04dae5427e8597921ab12f5c56e Mon Sep 17 00:00:00 2001
From: kevin <kevin@larke.org>
Date: Tue, 25 Jul 2023 20:20:45 -0400
Subject: [PATCH] cwText.h/cpp : Added isInteger(), isReal(), isIdentifier().

---
 cwText.cpp | 38 ++++++++++++++++++++++++++++++++++++++
 cwText.h   |  7 ++++++-
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/cwText.cpp b/cwText.cpp
index eebaf8e..d9009df 100644
--- a/cwText.cpp
+++ b/cwText.cpp
@@ -82,6 +82,44 @@ const char* cw::nextNonWhiteChar( const char* s )
 const char* cw::nextNonWhiteCharEOS( const char* s )
 { return _nextNonWhiteChar(s,true); }
 
+bool cw::isInteger( const char* s )
+{
+  for(; *s; ++s)
+    if(!isdigit(*s))
+      return false;
+  return true;
+}
+
+bool cw::isReal( const char* s)
+{
+  unsigned decN = 0;
+  for(; *s; ++s)
+    if( *s == '.' )
+    {
+      if( ++decN > 1)
+        return false;
+    }   
+    else
+    {
+      if(!isdigit(*s))
+        return false;
+    }
+  
+  return true;
+}
+
+bool cw::isIdentifier( const char* s )
+{
+  if( !isalpha(*s) && *s != '_' )
+    return false;
+
+  for(++s; *s; ++s)
+    if( !isalnum(*s) && *s != '_' )
+      return false;
+
+  return true;
+}
+
 
 char* cw::textJoin( const char* s0, const char* s1 )
 {
diff --git a/cwText.h b/cwText.h
index 5adb82c..081ee21 100644
--- a/cwText.h
+++ b/cwText.h
@@ -7,7 +7,7 @@ namespace cw
   // Return 0 if s is null.
   unsigned textLength( const char* s );
   
-  // if both s0 and s1 are nullptr then a match is indicated
+  // Note: if both s0 and s1 are nullptr then a match is indicated
   int textCompare( const char* s0, const char* s1 );
   int textCompare( const char* s0, const char* s1, unsigned n);
   
@@ -36,6 +36,11 @@ namespace cw
   // or nullptr if 's' is null.
   const char* nextNonWhiteCharEOS( const char* s );
 
+  
+  bool isInteger( const char* );        // text contains only [0-9]
+  bool isReal( const char* );           // text contains only [0-9] with one decimal place
+  bool isIdentifier( const char* );      // text is a legal id [0-9,A-Z,a-z,_] w/o leading number
+
   // Join s0 and s1 to form one long string.  Release the returned string with mem::free()
   char* textJoin( const char* s0, const char* s1 );