Lex Tutorial - Revision history

Mkwiki at 08:11, 3 August 2021

2021-08-03T08:11:43Z

2021-08-02T18:34:22Z

2021-08-02T18:33:51Z

2021-08-02T16:21:57Z

2020-08-13T17:38:15Z

The function of Lex is as follows:

2020-08-13T17:37:31Z

The function of Lex is as follows:

2020-08-13T17:37:11Z

The function of Lex is as follows:

2020-08-13T17:35:29Z

The Lex Format

2020-08-13T17:23:10Z

The Lex Format

2020-08-13T17:18:47Z

The Lex Format

@@ Line 1: / Line 1: @@
 [[File:Compilation phases.png|thumb|Phases of Compilation]]
-During the first phase the compiler reads the input and converts strings in the source to '''tokens'''.
+During the first phase, the compiler reads the input and converts strings in the source to '''tokens'''.
 * With '''regular expressions''' we can specify '''patterns''' to lex so it can generate code that will allow it to scan and match strings in the input.
 * Each pattern specified in the input to lex has an '''associated action'''. Typically an action '''returns a token''' that represents the matched string for subsequent use by the parser.

@@ Line 1: / Line 1: @@
 [[File:Compilation phases.png|thumb|Phases of Compilation]]
 During the first phase the compiler reads the input and converts strings in the source to '''tokens'''.
-* With '''regular expressions''' we can '''specify patterns''' to lex so it can generate code that will allow it to scan and match strings in the input.
+* With '''regular expressions''' we can specify '''patterns''' to lex so it can generate code that will allow it to scan and match strings in the input.
 * Each pattern specified in the input to lex has an '''associated action'''. Typically an action '''returns a token''' that represents the matched string for subsequent use by the parser.
 * Initially we will simply print the matched string rather than return a token value.<sup>[1]</sup>

@@ Line 1: / Line 1: @@
 [[File:Compilation phases.png|thumb|Phases of Compilation]]
 During the first phase the compiler reads the input and converts strings in the source to '''tokens'''.
-* With '''regular expressions''' we can specify patterns to lex so it can generate code that will allow it to scan and match strings in the input.
+* With '''regular expressions''' we can '''specify patterns''' to lex so it can generate code that will allow it to scan and match strings in the input.
-* Each pattern specified in the input to lex has an associated action. Typically an action returns a token that represents the matched string for subsequent use by the parser.
+* Each pattern specified in the input to lex has an '''associated action'''. Typically an action '''returns a token''' that represents the matched string for subsequent use by the parser.
 * Initially we will simply print the matched string rather than return a token value.<sup>[1]</sup>

@@ Line 1: / Line 1: @@
 [[File:Compilation phases.png|thumb|Phases of Compilation]]
-During the first phase the compiler reads the input and converts strings in the source to tokens. With regular expressions we can specify patterns to lex so it can generate code that will allow it to scan and match strings in the input. Each pattern specified in the input to lex has an associated action. Typically an action returns a token that represents the matched string for subsequent use by the parser. Initially we will simply print the matched string rather than return a token value.<sup>[1]</sup>
+During the first phase the compiler reads the input and converts strings in the source to '''tokens'''.
 ==Lex ==

@@ Line 8: / Line 8: @@
 ==The function of Lex is as follows:==
 * Firstly lexical analyzer creates a program '''lex.l''' in the Lex language. Then Lex compiler runs the '''lex.l''' program and produces a C program '''lex.yy.c.'''
 * Finally C compiler runs the '''lex.yy.c''' program and produces an object program '''a.out.'''
-* '''a.out''' is lexical analyzer that transforms an input stream into a '''sequence of tokens.''' <br>
+* '''a.out''' is lexical analyzer that transforms an input stream into a '''sequence of tokens.''' <br><br>
 [[File:Lex.png|center| Running Lex Programs ]]

@@ Line 30: / Line 30: @@
 <hr>
 . web: https://www.epaperpress.com/lexandyacc/index.html [ LEX & YACC TUTORIAL by Tom Niemann ] <br>
-. web: https://www.javatpoint.com/lex}
+. web: https://www.javatpoint.com/lex

@@ Line 29: / Line 29: @@
 <hr>
-. web: https://www.epaperpress.com/lexandyacc/prl.html
+. web: https://www.epaperpress.com/lexandyacc/prl.html <br>
 . web: https://www.javatpoint.com/lex}