Add text_file example, and partially implemented simple_expressions example

simple_examples/simple_expressions.pas

@@ -0,0 +1,18 @@
+program simple_expressions;
+
+{$mode objfpc}{$H+}
+
+var
+  b: Byte = 4;
+  c: Byte = 3;
+
+begin
+  WriteLn('Initial value of b is ', b, '; initial value of c is ', c, sLineBreak);
+  b := b shr 1; // >> shift right
+  c := shl 4; // << shift left
+  WriteLn('After b shr 1, b is ', b, '; after c shl 4, c is ', c, sLineBreak);
+  WriteLn('c xor b = ',c xor b, '; c and b = ', c and b, '; c or b,'
+  {$IFDEF WINDOWS}
+  ReadLn;
+  {$ENDIF}
+end.

text_file/text_file.lpi

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<CONFIG>
+  <ProjectOptions>
+    <Version Value="11"/>
+    <PathDelim Value="\"/>
+    <General>
+      <Flags>
+        <MainUnitHasCreateFormStatements Value="False"/>
+        <MainUnitHasTitleStatement Value="False"/>
+        <MainUnitHasScaledStatement Value="False"/>
+      </Flags>
+      <SessionStorage Value="InProjectDir"/>
+      <MainUnit Value="0"/>
+      <Title Value="text_file"/>
+      <UseAppBundle Value="False"/>
+      <ResourceType Value="res"/>
+    </General>
+    <BuildModes Count="1">
+      <Item1 Name="Default" Default="True"/>
+    </BuildModes>
+    <PublishOptions>
+      <Version Value="2"/>
+      <UseFileFilters Value="True"/>
+    </PublishOptions>
+    <RunParams>
+      <FormatVersion Value="2"/>
+      <Modes Count="0"/>
+    </RunParams>
+    <Units Count="1">
+      <Unit0>
+        <Filename Value="text_file.lpr"/>
+        <IsPartOfProject Value="True"/>
+      </Unit0>
+    </Units>
+  </ProjectOptions>
+  <CompilerOptions>
+    <Version Value="11"/>
+    <PathDelim Value="\"/>
+    <Target>
+      <Filename Value="text_file"/>
+    </Target>
+    <SearchPaths>
+      <IncludeFiles Value="$(ProjOutDir)"/>
+      <UnitOutputDirectory Value="lib\$(TargetCPU)-$(TargetOS)"/>
+    </SearchPaths>
+  </CompilerOptions>
+  <Debugging>
+    <Exceptions Count="3">
+      <Item1>
+        <Name Value="EAbort"/>
+      </Item1>
+      <Item2>
+        <Name Value="ECodetoolError"/>
+      </Item2>
+      <Item3>
+        <Name Value="EFOpenError"/>
+      </Item3>
+    </Exceptions>
+  </Debugging>
+</CONFIG>

text_file/text_file.lpr

@@ -0,0 +1,47 @@
+program text_file;
+
+{$mode objfpc}{$H+}
+
+uses sysutils;
+
+var
+  txtF: TextFile;
+  s: String;
+
+procedure ReadTenLines;
+const lineNo: integer = 0;
+var linesRead: integer = 0;
+begin
+  while not EOF(txtF) and (linesRead < 10) do
+  begin
+    ReadLn(txtF, s); // Read the current line in the file, and store in s
+    Inc(linesRead); // linesRead += 1
+    Inc(lineNo);
+    s := Format('Line %d: %s', [lineNo, s]);
+    WriteLn(s);
+  end;
+end;
+
+begin
+  AssignFile(txtF, 'text_file.lpr'); // Open pointer to the file
+  Reset(txtF); // Open existing file
+  WriteLn('Lines from text_file.lpr will be displayed 10 at a time');
+  WriteLn;
+
+  // Read and display the file
+  try
+    while not EOF(txtF) do
+    begin
+      ReadTenLines;
+      WriteLn;
+      WriteLn('Press [Enter] to continue');
+      ReadLn;
+    end;
+  finally
+    CloseFile(txtF);
+  end;
+
+  Write('End of file reached. Press [Enter] to finish');
+  ReadLn;
+end.
+