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Code Issues Releases Wiki Activity

Try a new syntax for operation cases.

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This commit is contained in:
Daniel Hillerström
2020-10-02 22:45:51 +01:00
parent 92aed1134a
commit d767e78b44
2 changed files with 58 additions and 39 deletions
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40
macros.tex
View File

@@ -1,3 +1,20 @@
%%
%% Defined-as equality
%%
\newcommand{\defas}[0]{\mathrel{\overset{\makebox[0pt]{\mbox{\normalfont\tiny\text{def}}}}{=}}}
\newcommand{\defnas}[0]{\mathrel{:=}}
\newcommand{\simdefas}[0]{\mathrel{\overset{\makebox[0pt]{\mbox{\normalfont\tiny\text{def}}}}{\simeq}}}
%%
%% Partiality
%%
\newcommand{\pto}[0]{\ensuremath{\rightharpoonup}}
%%
%% Operation arrows
%%
\newcommand{\opto}[0]{\ensuremath{\twoheadrightarrow}}
%%
%% Calculi names.
%%
@@ -33,6 +50,10 @@
\newcommand{\Else}{\keyw{else}}
\newcommand{\Absurd}{\keyw{absurd}}
\newcommand{\Record}[1]{\ensuremath{\langle #1 \rangle}}
\newcommand{\Op}[1]{\ensuremath{\langle\!\!\langle #1 \rangle\!\!\rangle}}
%\newcommand{\Op}[1]{\ensuremath{\{#1\}}}
\newcommand{\OpCase}[3]{\Op{#1~#2 \opto #3}}
\newcommand{\ExnCase}[2]{\Op{#1~#2}}
\newcommand{\Unit}{\Record{}}
\newcommand{\Inl}{\keyw{inl}}
\newcommand{\Inr}{\keyw{inr}}
@@ -178,23 +199,6 @@
\newenvironment{smathpar}{\vspace{-3ex}\small\begin{mathpar}}{\end{mathpar}\normalsize\ignorespacesafterend}
%%
%% Defined-as equality
%%
\newcommand{\defas}[0]{\mathrel{\overset{\makebox[0pt]{\mbox{\normalfont\tiny\text{def}}}}{=}}}
\newcommand{\defnas}[0]{\mathrel{:=}}
\newcommand{\simdefas}[0]{\mathrel{\overset{\makebox[0pt]{\mbox{\normalfont\tiny\text{def}}}}{\simeq}}}
%%
%% Partiality
%%
\newcommand{\pto}[0]{\ensuremath{\rightharpoonup}}
%%
%% Operation arrows
%%
\newcommand{\opto}[0]{\ensuremath{\twoheadrightarrow}}
%%
%% Lists
%%
@@ -370,3 +374,5 @@
\newcommand{\concatMap}{\dec{concatMap}}
\newcommand{\State}{\dec{State}}
\newcommand{\runState}{\dec{runState}}
\newcommand{\Uget}{\dec{get}}
\newcommand{\Uput}{\dec{put}}

55
thesis.tex
View File

@@ -1709,20 +1709,23 @@ no predefined dynamic semantics. The introduction form for effectful
operations is a computation term.
%
\begin{syntax}
&M,N \in \CompCat &::=& \cdots \mid~ \tikzmarkin{do1} (\Do \; \ell~V)^E \tikzmarkend{do1}
\slab{Value types} &A,B \in \ValTypeCat &::=& \cdots \mid~ \tikzmarkin{optype} A \opto B \tikzmarkend{optype}\\
\slab{Computations} &M,N \in \CompCat &::=& \cdots \mid~ \tikzmarkin{do1} (\Do \; \ell~V)^E \tikzmarkend{do1}
\end{syntax}
%
\dhil{Describe the operation arrow.}
%
Informally, the intended behaviour of the new computation term
$(\Do\; \ell~V)^E$ is that it performs some operation $\ell$ with
value argument $V$. Thus the $\Do$-construct is similar to the typical
exception-signalling $\keyw{throw}$ or $\keyw{raise}$ constructs found
in programming languages with support for exceptions. The term is
annotated with an effect row $E$, providing a handle to obtain the
current effect context. We make use of this effect row during typing:
current effect context. We make use of this effect row during typing.
%
\begin{mathpar}
\inferrule*[Lab=\tylab{Do}]
{ E = \{\ell : A \to B; R\} \\
{ E = \{\ell : A \opto B; R\} \\
\typ{\Delta}{E} \\
\typ{\Delta;\Gamma}{V : A}
}
@@ -1781,7 +1784,7 @@ syntactic category of handler definitions.
\begin{syntax}
\slab{Computations} &M,N \in \CompCat &::=& \cdots \mid~ \tikzmarkin{deephandlers1} \Handle \; M \; \With \; H\tikzmarkend{deephandlers1}\\[1ex]
\slab{Handlers} &H \in \HandlerCat &::=& \{ \Return \; x \mapsto M \}
\mid \{ \ell \; p \; r \mapsto N \} \uplus H\\
\mid \{ \OpCase{\ell}{p}{r} \mapsto N \} \uplus H\\
\slab{Terms} &t \in \TermCat &::=& \cdots \mid~ \tikzmarkin{handlerdefs} H \tikzmarkend{handlerdefs}
\end{syntax}
%
@@ -1789,14 +1792,14 @@ The handle construct $(\Handle \; M \; \With \; H)$ is the counterpart
to $\Do$. It runs computation $M$ using handler $H$. A handler $H$
consists of a return clause $\{\Return \; x \mapsto M\}$ and a
possibly empty set of operation clauses
$\{\ell \; p_\ell \; r_\ell \mapsto N_\ell\}_{\ell \in \mathcal{L}}$.
$\{\OpCase{\ell}{p_\ell}{r_\ell} \mapsto N_\ell\}_{\ell \in \mathcal{L}}$.
%
The return clause $\{\Return \; x \mapsto M\}$ defines how to
interpret the final return value of a handled computation. The
variable $x$ is bound to the final return value in the body $M$.
%
Each operation clause
$\{\ell \; p_\ell \; r_\ell \mapsto N_\ell\}_{\ell \in \mathcal{L}}$
$\{\OpCase{\ell}{p_\ell}{r_\ell} \mapsto N_\ell\}_{\ell \in \mathcal{L}}$
defines how to interpret an invocation of a particular operation
$\ell$. The variables $p_\ell$ and $r_\ell$ are bound in the body
$N_\ell$: $p_\ell$ binds the argument carried by the operation and
@@ -1807,7 +1810,7 @@ particular operation or the return clause; for these purposes we
define two convenient projections on handlers in the metalanguage.
\[
\ba{@{~}r@{~}c@{~}l@{~}l}
\hell &\defas& \{\ell\; p\; r \mapsto N \}, &\quad \text{where } \{\ell\; p\; r \mapsto N \} \in H\\
\hell &\defas& \{\OpCase{\ell}{p}{r} \mapsto N \}, &\quad \text{where } \{\OpCase{\ell}{p}{r} \mapsto N \} \in H\\
\hret &\defas& \{\Return\; x \mapsto N \}, &\quad \text{where } \{\Return\; x \mapsto N \} \in H\\
\ea
\]
@@ -1822,7 +1825,7 @@ labels it handles, i.e.
\begin{equations}
\dom &:& \HandlerCat \to \LabelCat\\
\dom(\{\Return\;x \mapsto M\}) &\defas& \emptyset\\
\dom(\{\ell\; p\;r \mapsto M\} \uplus H) &\defas& \{\ell\} \cup \dom(H)
\dom(\{\OpCase{\ell}{p}{r} \mapsto M\} \uplus H) &\defas& \{\ell\} \cup \dom(H)
\end{equations}
\subsection{Static semantics}
@@ -1842,9 +1845,9 @@ typing of the $\Do$-construct.
%\mprset{flushleft}
\inferrule*[Lab=\tylab{Handler}]
{{\bl
C = A \eff \{(\ell_i : A_i \to B_i)_i; R\} \\
C = A \eff \{(\ell_i : A_i \opto B_i)_i; R\} \\
D = B \eff \{(\ell_i : P_i)_i; R\}\\
H = \{\Return\;x \mapsto M\} \uplus \{ \ell_i\;p_i\;r_i \mapsto N_i \}_i
H = \{\Return\;x \mapsto M\} \uplus \{ \OpCase{\ell_i}{p_i}{r_i} \mapsto N_i \}_i
\el}\\\\
\typ{\Delta;\Gamma, x : A}{M : D}\\\\
[\typ{\Delta;\Gamma,p_i : A_i, r_i : B_i \to D}{N_i : D}]_i
@@ -1879,7 +1882,7 @@ for handling return values and another for handling operations.
&\reducesto& N[V/p, \lambda y . \, \Handle \; \EC[\Return \; y] \; \With \; H/r], \\
\multicolumn{4}{@{}r@{}}{
\hfill\ba[t]{@{~}r@{~}l}
\text{where}& \hell = \{ \ell \; p \; r \mapsto N \}\\
\text{where}& \hell = \{ \OpCase{\ell}{p}{r} \mapsto N \}\\
\text{and} & \ell \notin \BL(\EC)
\ea
}
@@ -1912,8 +1915,8 @@ $\ell$.
\[
\bl
\ba{@{~}r@{~}c@{~}l}
H_{\mathsf{inner}} &\defas& \{\ell\;p\;r \mapsto r~42; \Return\;x \mapsto \Return~x\}\\
H_{\mathsf{outer}} &\defas& \{\ell\;p\;r \mapsto r~0;\Return\;x \mapsto \Return~x \}
H_{\mathsf{inner}} &\defas& \{\OpCase{\ell}{p}{r} \mapsto r~42; \Return\;x \mapsto \Return~x\}\\
H_{\mathsf{outer}} &\defas& \{\OpCase{\ell}{p}{r} \mapsto r~0;\Return\;x \mapsto \Return~x \}
\ea\medskip\\
\Handle \;
\left(\Handle\; \Do\;\ell~\Record{}\;\With\; H_{\mathsf{inner}}\right)\;
@@ -2070,7 +2073,7 @@ Let us define a suitable handler for this operation.
\Handle\;m\,\Unit\;\With\\
~\ba{@{~}l@{~}c@{~}l}
\Return\;res &\mapsto& \Record{res;\nil}\\
\Putc~\Record{\_;c}~resume &\mapsto&
\OpCase{\Putc}{\Record{\_;c}}{resume} &\mapsto&
\Let\; \Record{res;file} = resume\,\Unit\;\In\;
\Record{res; c \cons file}
\ea
@@ -2141,7 +2144,7 @@ We can now write some contents to the file and observe the effects.
\Handle\;m\,\Unit\;\With\\
~\ba{@{~}l@{~}c@{~}l}
\Return\;\_ &\mapsto& 0\\
\Exit~n~\_ &\mapsto& n
\ExnCase{\Exit}{n} &\mapsto& n
\ea
\ea
\el
@@ -2213,7 +2216,7 @@ The following handler implements the environment.
\Handle\;m\,\Unit\;\With\\
~\ba{@{~}l@{~}c@{~}l}
\Return\;res &\mapsto& res\\
\Ask~\Unit~resume &\mapsto&
\OpCase{\Ask}{\Unit}{resume} &\mapsto&
\bl
\Case\;user\,\{
\ba[t]{@{}l@{~}c@{~}l}
@@ -2267,7 +2270,7 @@ string.
\Handle\;m\,\Unit\;\With\\
~\ba{@{~}l@{~}c@{~}l}
\Return\;res &\mapsto& res\\
\Su~user'~resume &\mapsto& \environment\,\Record{user';resume})\rangle
\OpCase{\Su}{user'}{resume} &\mapsto& \environment\,\Record{user';resume})\rangle
\ea
\ea
\el
@@ -2306,7 +2309,7 @@ string.
\Handle\;m\,\Unit\;\With\\
~\ba{@{~}l@{~}c@{~}l}
\Return\;res &\mapsto& [res]\\
\Fork~\Unit~resume &\mapsto& resume~\True \concat resume~\False
\OpCase{\Fork}{\Unit}{resume} &\mapsto& resume~\True \concat resume~\False
\ea
\ea
\el
@@ -2335,7 +2338,7 @@ string.
\Handle\;m\,\Unit\;\With\\
~\ba{@{~}l@{~}c@{~}l}
\Return\;res &\mapsto& \Done~res\\
\Interrupt~\Unit~resume &\mapsto& \Suspended~resume
\OpCase{\Interrupt}{\Unit}{resume} &\mapsto& \Suspended~resume
\ea
\ea
\el
@@ -2370,6 +2373,16 @@ string.
\State~\alpha \defas \{\Get:\UnitType \opto \alpha;\Put:\alpha \opto \UnitType\}
\]
\[
\bl
\Uget : \UnitType \to \alpha \eff \{\Get:\UnitType \opto \alpha\}\\
\Uget~\Unit \defas \Do\;\Get~\Unit \medskip\\
\Uput : \UnitType \to \alpha \eff \{\Put:\alpha \opto \Unit\}\\
\Uput~st \defas \Do\;\Put~st
\el
\]
\[
\bl
\runState : \Record{\beta;\UnitType \to \alpha \eff \State~\beta} \to \Record{\alpha;\beta}\\
@@ -2380,8 +2393,8 @@ string.
\Handle\;m\,\Unit\;\With\\
~\ba{@{~}l@{~}c@{~}l}
\Return\;res &\mapsto& \lambda st.\Record{res;st}\\
\Get~\Unit~resume &\mapsto& \lambda st.resume~st~st\\
\Put~st'~resume &\mapsto& \lambda st.resume~\Unit~st'
\OpCase{\Get}{\Unit}{resume} &\mapsto& \lambda st.resume~st~st\\
\OpCase{\Put}{st'}{resume} &\mapsto& \lambda st.resume~\Unit~st'
\ea
\ea\\
\In\; f\,st_0