summaryrefslogtreecommitdiff
path: root/doc
diff options
context:
space:
mode:
authorGravatar Adam Chlipala <adamc@hcoop.net>2008-11-27 15:27:17 -0500
committerGravatar Adam Chlipala <adamc@hcoop.net>2008-11-27 15:27:17 -0500
commit5e3c42711e20b42ba7f850cc5800f01cbfee3f05 (patch)
treef4741e8d826bb26273363f3b9dc2d599d6bc57f0 /doc
parenta9c2432822c68cfc0897c162b17af6b69d0e22b7 (diff)
Expressions
Diffstat (limited to 'doc')
-rw-r--r--doc/manual.tex41
1 files changed, 40 insertions, 1 deletions
diff --git a/doc/manual.tex b/doc/manual.tex
index 01f5a5f3..18879a50 100644
--- a/doc/manual.tex
+++ b/doc/manual.tex
@@ -5,6 +5,8 @@
\newcommand{\mt}[1]{\mathsf{#1}}
\newcommand{\rc}{+ \hspace{-.075in} + \;}
+\newcommand{\rcut}{\; \texttt{--} \;}
+\newcommand{\rcutM}{\; \texttt{---} \;}
\begin{document}
@@ -26,7 +28,7 @@ We give the Ur language definition in \LaTeX $\;$ math mode, since that is prett
$\times$ & \cd{*} \\
$\lambda$ & \cd{fn} \\
$\Rightarrow$ & \cd{=>} \\
- $\rc$ & \cd{++} \\
+ & \cd{---} \\
\\
$x$ & Normal textual identifier, not beginning with an uppercase letter \\
$X$ & Normal textual identifier, beginning with an uppercase letter \\
@@ -37,6 +39,8 @@ We often write syntax like $e^*$ to indicate zero or more copies of $e$, $e^+$ t
We write $\ell$ for literals of the primitive types, for the most part following C conventions. There are $\mt{int}$, $\mt{float}$, and $\mt{string}$ literals.
+This version of the manual doesn't include operator precedences; see \texttt{src/urweb.grm} for that.
+
\subsection{Core Syntax}
\emph{Kinds} classify types and other compile-time-only entities. Each kind in the grammar is listed with a description of the sort of data it classifies.
@@ -47,6 +51,7 @@ $$\begin{array}{rrcll}
&&& \kappa \to \kappa & \textrm{type-level functions} \\
&&& \{\kappa\} & \textrm{type-level records} \\
&&& (\kappa\times^+) & \textrm{type-level tuples} \\
+ &&& \_ & \textrm{wildcard} \\
&&& (\kappa) & \textrm{explicit precedence} \\
\end{array}$$
@@ -80,6 +85,7 @@ $$\begin{array}{rrcll}
\\
&&& \lambda [c \sim c] \Rightarrow c & \textrm{guarded constructor} \\
\\
+ &&& \_ & \textrm{wildcard} \\
&&& (c) & \textrm{explicit precedence} \\
\end{array}$$
@@ -116,9 +122,42 @@ $$\begin{array}{rrcll}
&&& \hat{X} \; p & \textrm{unary constructor} \\
&&& \{(x = p,)^*\} & \textrm{rigid record pattern} \\
&&& \{(x = p,)^+, \ldots\} & \textrm{flexible record pattern} \\
+ &&& (p) & \textrm{explicit precedence} \\
\\
\textrm{Qualified capitalized variable} & \hat{X} &::=& X & \textrm{not from a module} \\
&&& M.X & \textrm{projection from a module} \\
\end{array}$$
+\emph{Expressions} are the main run-time entities, corresponding to both ``expressions'' and ``statements'' in mainstream imperative languages.
+$$\begin{array}{rrcll}
+ \textrm{Expressions} & e &::=& e : \tau & \textrm{type annotation} \\
+ &&& x & \textrm{variable} \\
+ &&& \ell & \textrm{constant} \\
+ \\
+ &&& e \; e & \textrm{function application} \\
+ &&& \lambda x : \tau \Rightarrow e & \textrm{function abstraction} \\
+ &&& e [c] & \textrm{polymorphic function application} \\
+ &&& \lambda x \; ? \; \kappa \Rightarrow e & \textrm{polymorphic function abstraction} \\
+ \\
+ &&& \{(c = e,)^*\} & \textrm{known-length record} \\
+ &&& e.c & \textrm{record field projection} \\
+ &&& e \rc e & \textrm{record concatenation} \\
+ &&& e \rcut c & \textrm{removal of a single record field} \\
+ &&& e \rcutM c & \textrm{removal of multiple record fields} \\
+ &&& \mt{fold} & \textrm{fold over fields of a type-level record} \\
+ \\
+ &&& \mt{let} \; ed^* \; \mt{in} \; e \; \mt{end} & \textrm{local definitions} \\
+ \\
+ &&& \mt{case} \; e \; \mt{of} \; (p \Rightarrow e|)^+ & \textrm{pattern matching} \\
+ \\
+ &&& \lambda [c \sim c] \Rightarrow e & \textrm{guarded expression} \\
+ \\
+ &&& \_ & \textrm{wildcard} \\
+ &&& (e) & \textrm{explicit precedence} \\
+ \\
+ \textrm{Local declarations} & ed &::=& \cd{val} \; x : \tau = e & \textrm{non-recursive value} \\
+ &&& \cd{val} \; \cd{rec} \; (x : \tau = e \; \cd{and})^+ & \textrm{mutually-recursive values} \\
+\end{array}$$
+
+
\end{document} \ No newline at end of file