18 Tokens, Category Codes, Verbatim Modes -- 18.1 Tokens -- 18.2 Active Characters -- 18.3 Verbatim Modes -- 18.4 Uppercase and Lowercase Characters, \uccode, \lccode, \uppercase, etc -- 18.5 Summary -- 19 More on Tokens -- 19.1 Converting Character Strings to Tokens, and Tokens Back to Character Strings -- 19.2 Array Macros -- 19.3 Cross-Referencing Using \csname...\endcsname -- 19.4 Curly Braces -- 19.5 Summary -- 20 Token Registers, TfeX List Processing -- 20.1 Token Registers -- 20.2 TEX Lists -- 20.3 Using TfeK Lists for the Emulation of Arrays -- 20.4 Summary -- 21 Macros -- 21.1 Assigning a Meaning to a Control Sequence -- 21.2 Primitive Control Sequences -- 21.3 Macros -- 21.4 Some Simple Macro Examples -- 21.5 The Theory of Macro Definitions -- 21.6 Macro Definitions Using \outer -- 21.7 Macros with Parameters -- 21.8 Macros with Undelimited Parameters -- 21.9 Macros with Delimited Parameters -- 21.10 Mixed Parameter Types -- 21.11 Spaces after Macro Calls, \ignorespaces -- 21.12 Summary -- 22 Macros, Expansion Issues -- 22.1 Expanded Macro Definitions, \edef -- 22.2 Macro Expansion -- 22.3 Placement of Macro Calls and Arguments -- 22.4 Category Codes and Parameters -- 22.5 Nested Macro Definitions -- 22.6.Defining "\long"Macros -- 22.7.Organizing Your Own Macros -- 22.8 Keyword Parameters -- 22.9 Summary -- 23 More on Macro-Related Items -- 23.1 \afterassignment -- 23.2 \Let: Making Control Sequences Equivalent -- 23.3. \let and Undefined Tokens -- 23.4 Looking Ahead with \futurelet -- 23.5 Summary -- Advanced Macro Concepts -- 24.1 Changing the Order of Expansion, \expandafetr -- 24.2 Suppressing Expansion with \noexpand -- 24.3 The Almighty \the -- 24.4 When No Exoansion Takes Place -- 24.5 Summary -- Conditional and Their Applications -- 25.1 Conditionals -- 25.2 Conforming Conditionals -- 25.3 Summary -- Date and Calendar Macros -- 26.1 The Earliest Date Accommodated by the Presented Macros -- 26.2 Copying Date, \CopyDate -- 26.3 Codes for the Days of a Week -- 26.4 Print a Month, \ProvideMonth -- 26.5 Check for the Legality of a Year: \CheckLegalYear -- 26.6 Check for the Legality of Month: \CheckLegalMonth -- 26.7 Compute the Number of Days in a Month, \NumberOfDaysInMonth -- 26.8 Check for the Validity of a Date -- 26.9 Is a Year a Leap Year? -- 26.10 Compute the Number of Days in Year -- 26.11 Compute the Date of the Following Day -- 26.12 Compute the Date of the Previous Day -- 26.13 Compute the Same Day of the Week in the Next or Previous Week -- 26.14 Compute the Next Month -- 26.15 Compute the Previous Month -- 26.16 Compute the Day of the Week of an Arbitrary Date -- 26.17 Printing Today's Date -- 26.18 Compute The Monday of the Same Week of Some Given Date -- 26.19 Small Monthly Calendars -- 26.20 Printing a Group of Three Monthly Calendars -- 26.21 A Yearly Calendar Macro -- 26.22 Compute the Week Number of a Date Within a Year -- 26.23 Loading All Date-Related Macros -- 26.24 Summary -- Recursion, Loop Constructs, Modes, testing of TEX Code and Related Items -- 27.1 Recursive Macros and Loops in TEX -- 27.2. Enumeration Macro Definitions -- 27.3. Box Register Queue Macros -- 27.4 \relax -- 27.5 \jobname -- 27.6 \Environments -- 27.7 Modes -- 27.8 LATEX and the Plain Format -- 27.9 Debugging TEX MAcros and TEX Code in General -- 27.10 User Macro Error Messages, \errmessage, \errhelp -- 27.11 The Definition of Macro \tracingall -- 27.12 Writing to the Log File and the Terminal, \pausing -- 27.13 Summary -- Reading From and Writing To Files -- 28.1 File Names in TEX -- 28.2 Reading from a File on a Line-By-Line Basis -- 28.3 Reading-In a Complete File, \input -- 28.4 More \input Related MAcros -- 28.5 Writing to a File -- 28.6 Summary -- More on Input and Output -- 29.1 Index File Writing -- 29.2 Writing Table of Contents Files -- 29.3 Verbatim Writing to Files -- 29.4 Macros to Write Endnotes -- 29.5 Writing to the Log File and the Terminal -- 29.6 Protocol File Writing -- 29.7 Comparing Two Files -- 29.8 \shipout, \tracingoutput, \deadcycles, \maxdeadcycles -- 29.9 \special -- 29.10 Summary -- Partial Processing of a Document -- 30.1 A General Overview of the Macros of this Chapter -- 30.2 Main Document and Part Source Files, Auxiliary Files -- 30.3 Macros for the Partial Processing of a Document -- 30.4 Administrative Files -- 30.5 The Generation of a Table of Contents -- 30.6 Putting the Pieces Together -- 30.7 Macros Source Files -- 30.8 Cross-Referencing Macros for Partial Processing Macros -- 30.9 Summary -- More on the Partial Processing of a Documents -- 31.1 An Example Application -- 31.2 The Partial Processing Macros Used to Typeset This Series -- 31.3 The TEXIP Format -- 31.4 Summary.