Get words out of a file in Ada - ada

Question

I have a folder with files containing some text. I am trying to go through all the files one after the other, and count how many times we see every word in the text files.
I know how to open the file, but once I'm in the file I don't know how to read each word one after the other, and go to the next word.
If anyone has some ideas to guide me it'd be great.

Answer 1

Read the file a line at a time into a string using Get_Line, then break the line up into the individual words.

Answer 2

Here's one way of doing it, I needed some playtime with the containers.
Using streams is still the best solution for your problem, given the multiple files.
Text_Search.ads
Pragma Ada_2012;
With
Ada.Containers.Indefinite_Ordered_Maps;
Package Text_Search with Elaborate_Body is
Text : Constant String :=
ASCII.HT &
"We hold these truths to be self-evident, that all men are created " &
"equal, that they are endowed by their Creator with certain unalienable "&
"Rights, that among these are Life, Liberty and the pursuit of " &
"Happiness.--That to secure these rights, Governments are instituted " &
"among Men, deriving their just powers from the consent of the governed" &
", --That whenever any Form of Government becomes destructive of these " &
"ends, it is the Right of the People to alter or to abolish it, and to " &
"institute new Government, laying its foundation on such principles " &
"and organizing its powers in such form, as to them shall seem most " &
"likely to effect their Safety and Happiness. Prudence, indeed, will " &
"dictate that Governments long established should not be changed for " &
"light and transient causes; and accordingly all experience hath shewn, "&
"that mankind are more disposed to suffer, while evils are sufferable, " &
"than to right themselves by abolishing the forms to which they are " &
"accustomed. But when a long train of abuses and usurpations, pursuing " &
"invariably the same Object evinces a design to reduce them under " &
"absolute Despotism, it is their right, it is their duty, to throw off " &
"such Government, and to provide new Guards for their future security." &
"now the necessity which constrains them to alter their former Systems " &
"of Government. The history of the present King of Great Britain is a " &
"history of repeated injuries and usurpations, all having in direct " &
"object the establishment of an absolute Tyranny over these States. To " &
"prove this, let Facts be submitted to a candid world.";
Package Word_List is New Ada.Containers.Indefinite_Ordered_Maps(
Key_Type => String,
Element_Type => Positive
);
Function Create_Map( Words : String ) Return Word_List.Map;
Words : Word_List.map;
End Text_Search;
Text_Search.adb
Package Body Text_Search is
Function Create_Map( Words : String ) Return Word_List.Map is
Delimiters : Array (Character) of Boolean:=
('.' | ' ' | '-' | ',' | ';' | ASCII.HT => True, Others => False);
Index, Start, Stop : Positive := Words'First;
begin
Return Result : Word_List.Map do
Parse:
loop
Start:= Index;
-- Ignore initial delimeters.
while Delimiters(Words(Start)) loop
Start:= 1+Start;
end loop;
Stop:= Start;
while not Delimiters(Words(Stop)) loop
Stop:= 1+Stop;
end loop;
declare
-- Because we stop *on* a delimiter we mustn't include it.
Subtype R is Positive Range Start..Stop-1;
Substring : String renames Words(R);
begin
-- if it's there, increment; otherwise add it.
if Result.Contains( Substring ) then
Result(Substring):= 1 + Result(Substring);
else
Result.Include( Key => substring, New_Item => 1 );
end if;
end;
Index:= Stop + 1;
end loop parse;
exception
When Constraint_Error => null; -- we run until our index fails.
end return;
End Create_Map;
Begin
Words:= Create_Map( Words => Text );
End Text_Search;
Test.adb
Pragma Ada_2012;
Pragma Assertion_Policy( Check );
With
Text_Search,
Ada.Text_IO;
Procedure Test is
Procedure Print_Word( Item : Text_Search.Word_List.Cursor ) is
use Text_Search.Word_List;
Word : String renames Key(Item);
Word_Column : String(1..20) := (others => ' ');
begin
Word_Column(1..Word'Length+1):= Word & ':';
Ada.Text_IO.Put_Line( Word_Column & Positive'Image(Element(Item)) );
End Print_Word;
Begin
Text_Search.Words.Iterate( Print_Word'Access );
End Test;

Answer 3

Instead of going by individual words, you could read the file a line at a time into a string using Get_Line, and then use regular expressions: Regular Expressions in Ada?

Answer 4

If you're using Ada 2012 here's how I would recommend doing it:
With Ada.Containers.Indefinite_Ordered_Maps.
Instantiate a Map with String as key, and Positive as Key;
Grab the string; I'd use either a single string or stream-processing.
Break the input-text into words; this can be done on-the-fly if you use streams.
When you get a word (from #4) add it to your map if it doesn't exist, otherwise increment the element.
When you are finished, just run a For Element of WORD_MAP Loop that prints the string & count.
There's several ways you could handle strings in #3:
Perfectly sized via recursive function call [terminating on a non-word character or the end of input].
Unbounded_String
Vector (Positive, Character) -- append for valid characters, convert to array [string] and add to the map when an invalid-character [or the end of input] is encountered -- working variable.
Not Null Access String working variable.