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% Document Info
\author{nsuarezcanton}
\pdfinfo{
  /Title (compilers.pdf)
  /Creator (Cheatography)
  /Author (nsuarezcanton)
  /Subject (Compilers Cheat Sheet)
}

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\fancyhead[L]{
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
    \SetRowColor{DarkBackground}
    \vspace{-7pt}
    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
    }
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\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Compilers Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{nsuarezcanton} via \textcolor{DarkBackground}{\uline{cheatography.com/27727/cs/8107/}}}
\end{tabulary}
\end{multicols}}

\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
  \SetRowColor{FootBackground}
  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}nsuarezcanton \\
  \uline{cheatography.com/nsuarezcanton} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 4th May, 2016.\\
   Updated 10th May, 2016.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
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  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}}  \\
  \SetRowColor{white}
  \vspace{-5pt}
  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
\end{tabulary}
\end{multicols}}




\begin{document}
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\begin{multicols*}{3}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Paramater Passing Mechanisms}}  \tn
% Row 0
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\mymulticolumn{1}{x{5.377cm}}{{\emph{Call-by-value:}}} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}Actual parameter is evaluated. It's value is placed in a the locating of the corresponding former parameter of the called procedure.} \tn 
% Row Count 4 (+ 4)
% Row 1
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\mymulticolumn{1}{x{5.377cm}}{{\emph{Call-by-reference:}}} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}Address of the actual parameter is passed to the value of the corresponding formal parameters. The expression is evaluated before the call, and its value is stored in a location of its own.} \tn 
% Row Count 10 (+ 6)
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\end{tabularx}
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\begin{tabularx}{5.377cm}{X}
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\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Parsing}}  \tn
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\mymulticolumn{1}{x{5.377cm}}{A {\emph{string of terminals}} -\textgreater{} Figure out how to derive it from the start symbol of the grammar (reports errors) (most fundamental problem of compilers). \newline % Row Count 3 (+ 3)
{\bf{Parse Tree:}} shows how the start symbol of a grammar derives a string in the language. \newline % Row Count 5 (+ 2)
{\bf{Ambiguous grammar:}} a grammar is said to be ambiguous when there are more than one parse trees for generating a given string of terminals.% Row Count 8 (+ 3)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Predictive Parsing}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{Top-down method for syntax analysis. Set of recursive procedures is used to process the input. Predictive parsing relies on the information about the first symbols that can be generated by a production body.% Row Count 5 (+ 5)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
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\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Tokens, Patterns and Lexemes}}  \tn
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\mymulticolumn{1}{x{5.377cm}}{Token} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}token name and an optional attribute value.} \tn 
% Row Count 2 (+ 2)
% Row 1
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\mymulticolumn{1}{x{5.377cm}}{Pattern} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}a description of the form that lexemes of a token may take.} \tn 
% Row Count 5 (+ 3)
% Row 2
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\mymulticolumn{1}{x{5.377cm}}{Lexeme} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}sequence of characters in the source program that matches a pattern for the token and is identified by the lexical analyzer as an instance of that token.} \tn 
% Row Count 10 (+ 5)
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\end{tabularx}
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\begin{tabularx}{5.377cm}{X}
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\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Syntax Directed Translator (SYNTAX)}}  \tn
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\mymulticolumn{1}{x{5.377cm}}{{\emph{Syntax:}}} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}of a programming language describes the proper form of its programs.} \tn 
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% Row 1
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\mymulticolumn{1}{x{5.377cm}}{{\emph{Semantics:}}} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}defines what its programs mean.} \tn 
% Row Count 5 (+ 2)
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\mymulticolumn{1}{x{5.377cm}}{{\emph{Grammar:}}} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}naturally describes the hierarchical structure of most programming languages.} \tn 
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\begin{tabularx}{5.377cm}{X}
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\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Associativity of Operators}}  \tn
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\mymulticolumn{1}{x{5.377cm}}{Left-associative} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}Addition, subtraction, multiplication and division.} \tn 
% Row Count 3 (+ 3)
% Row 1
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\mymulticolumn{1}{x{5.377cm}}{Right-associative} \tn 
\mymulticolumn{1}{x{5.377cm}}{\hspace*{6 px}\rule{2px}{6px}\hspace*{6 px}Exponentiation, "C" =} \tn 
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\begin{tabularx}{5.377cm}{p{0.4577 cm} x{2.83774 cm} x{1.28156 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Syntax-Directed Translation}}  \tn
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\mymulticolumn{3}{x{5.377cm}}{Done by attaching rules or program fragments to productions in grammars.} \tn 
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expr & -\textgreater{} & expr1 + term \tn 
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 & {\emph{Sum of two subexpressions}} &  \tn 
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\mymulticolumn{3}{x{5.377cm}}{{\bf{In pseudo-code:}}} \tn 
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 & Translate & expr1; \tn 
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% Row 5
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 & Translate & term; \tn 
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 & Handle & +; \tn 
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\hhline{>{\arrayrulecolor{DarkBackground}}---}
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\begin{tabularx}{5.377cm}{x{1.74195 cm} x{3.23505 cm} }
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\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Lexical Analyzer}}  \tn
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1.{\bf{Scanning}} & does not require tokenization. \tn 
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2.{\bf{Lexical Analysis}} & produces tokes from the output of the scanner. \tn 
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\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Abstract Syntax Tree (AST)}}  \tn
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\mymulticolumn{1}{x{5.377cm}}{- condensed form of parse trees \newline % Row Count 1 (+ 1)
- represent the syntax of a program. \newline % Row Count 2 (+ 1)
- collapse chains of productions into single steps \newline % Row Count 4 (+ 2)
- separate parsing from semantic checking \newline % Row Count 5 (+ 1)
- Can manipulate abstract syntax after concrete syntax has been checked \newline % Row Count 7 (+ 2)
- Can use syntax tree as intermediate representation \newline % Row Count 9 (+ 2)
STRUCTURE: \newline % Row Count 10 (+ 1)
-{}- a node represents program construct e.g. node for an operator \newline % Row Count 12 (+ 2)
-{}- children represent components of the construct e.g. nodes for operands% Row Count 14 (+ 2)
} \tn 
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\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Context-Free Grammar}}  \tn
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\mymulticolumn{1}{x{5.377cm}}{{\bf{1.}} A set of {\emph{terminal}} symbols (tokens). Elementary symbols of the language defined in its own grammar. \newline % Row Count 3 (+ 3)
{\bf{2.}} A set of {\emph{nonterminals}} (syntactic values). \newline % Row Count 5 (+ 2)
{\bf{3.}} A set of {\emph{productions}}. Each production consists of: (a) a {\emph{nonterminal}} which is the head of left side of the production, (b) an arrow, and (c) a sequence of terminals or non-terminals. \newline % Row Count 9 (+ 4)
{\bf{4.}} A designation of one of the nonterminals as the start symbol.% Row Count 11 (+ 2)
} \tn 
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\begin{tabularx}{5.377cm}{p{0.4977 cm} x{4.4793 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Top-Down Parsing}}  \tn
% Row 0
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\mymulticolumn{2}{x{5.377cm}}{The top-down construction of a parse tree is done by starting at the door, labelled with the starting nonterminal statement, and repeatedly parsing.} \tn 
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% Row 1
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1. & At node {\emph{N}}, labelled with a nonterminal {\emph{A}}, select one of the productions for A and construct a children at {\emph{N}} for the symbols in the production body. \tn 
% Row Count 8 (+ 5)
% Row 2
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2. & Find the next node at which a subtree is to be constructed, typically the leftmost unexpanded nonterminal of the tree. \tn 
% Row Count 12 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
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\begin{tabularx}{5.377cm}{x{1.78503 cm} x{1.8308 cm} x{0.96117 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Lexical Analysis}}  \tn
% Row 0
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\mymulticolumn{3}{x{5.377cm}}{Reads characters from input and groups them into "token objects." Along with a terminal symbol that is used for parsing decisions.} \tn 
% Row Count 3 (+ 3)
% Row 1
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Token & -\textgreater{} & \seqsplit{Terminal} + More Info. \tn 
% Row Count 6 (+ 3)
% Row 2
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{\emph{General approach to reading ahead on the input.}} & Maintain an input buffer from which the lexical analyzer can read and push back characters. &  \tn 
% Row Count 12 (+ 6)
% Row 3
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RegEx -\textgreater{} & NFA & -\textgreater{}DFA \tn 
% Row Count 13 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}---}
\end{tabularx}
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\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Symbol Tables}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{Map from identifiers to meanings. Keep track of  \newline % Row Count 1 (+ 1)
- {\emph{binding:}} associating a name with a location  \newline % Row Count 2 (+ 1)
- {\emph{scope:}} where in the program a name has meaning \newline % Row Count 4 (+ 2)
{\bf{USAGE:}} \newline % Row Count 5 (+ 1)
1. Lexical Analyzer: add entries to ST \newline % Row Count 6 (+ 1)
2. Parser: add type info, discover scope \newline % Row Count 7 (+ 1)
3. Semantic Analyzer: use type info to find semantic errors \newline % Row Count 9 (+ 2)
4. Code generator: determine where data are located, generate code to access locations% Row Count 11 (+ 2)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
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% That's all folks
\end{multicols*}

\end{document}