Index

Symbols

+r, GHCi options
+RTS, Running a compiled program
+s, GHCi options
+t, Using do-notation at the prompt, GHCi options
-#include, Options affecting the C compiler (if applicable)
--install-signal-handlers
RTS option, Miscellaneous RTS options
--RTS, Running a compiled program
--show-iface, Other options related to interface files
-?, Package management (the ghc-pkg command)
-A
RTS option, RTS options to control the garbage collector
-A<size> RTS option, Sooner: producing a program more quickly , Faster: producing a program that runs quicker
-auto, Profiling, Compiler options for profiling
-auto-all, Profiling, Compiler options for profiling
-B
RTS option, RTS options for hackers, debuggers, and over-interested souls
-C, Modes of operation, Batch compiler mode
-c, Modes of operation, Batch compiler mode, Options affecting linking
RTS option, RTS options to control the garbage collector
-caf-all, Rules for attributing costs, Compiler options for profiling
-cpp, Batch compiler mode, Options affecting the C pre-processor
-cpp option, Options affecting the C pre-processor
-cpp vs string gaps, CPP and string gaps
-Cs
RTS option, Using Concurrent Haskell
-D, Options affecting the C pre-processor
RTS option, RTS options for hackers, debuggers, and over-interested souls
-dcmm-lint, Checking for consistency
-dcore-lint, Warnings and sanity-checking, Checking for consistency
-dcore-lint option, When the compiler “does the wrong thing”
-ddump options, Dumping out compiler intermediate structures
-ddump-asm, Dumping out compiler intermediate structures
-ddump-bcos, Dumping out compiler intermediate structures
-ddump-cmm, Dumping out compiler intermediate structures
-ddump-cpranal, Dumping out compiler intermediate structures
-ddump-cse, Dumping out compiler intermediate structures
-ddump-deriv, Dumping out compiler intermediate structures
-ddump-ds, Dumping out compiler intermediate structures
-ddump-flatC, Dumping out compiler intermediate structures
-ddump-foreign, Dumping out compiler intermediate structures
-ddump-hi, Other options related to interface files
-ddump-hi-diffs, Other options related to interface files
-ddump-if-trace, Dumping out compiler intermediate structures
-ddump-inlinings, Dumping out compiler intermediate structures
-ddump-minimal-imports, Other options related to interface files
-ddump-occur-anal, Dumping out compiler intermediate structures
-ddump-opt-cmm, Dumping out compiler intermediate structures
-ddump-parsed, Dumping out compiler intermediate structures
-ddump-prep, Dumping out compiler intermediate structures
-ddump-rn, Dumping out compiler intermediate structures
-ddump-rn-trace, Dumping out compiler intermediate structures
-ddump-rules, Dumping out compiler intermediate structures
-ddump-simpl, Dumping out compiler intermediate structures
-ddump-simpl-iterations, Dumping out compiler intermediate structures
-ddump-simpl-stats option, Dumping out compiler intermediate structures
-ddump-spec, Dumping out compiler intermediate structures
-ddump-splices, Dumping out compiler intermediate structures
-ddump-stg, Dumping out compiler intermediate structures
-ddump-stranal, Dumping out compiler intermediate structures
-ddump-tc, Dumping out compiler intermediate structures
-ddump-tc-trace, Dumping out compiler intermediate structures
-ddump-types, Dumping out compiler intermediate structures
-ddump-workwrap, Dumping out compiler intermediate structures
-debug, Options affecting linking
-dfaststring-stats, Dumping out compiler intermediate structures
-dppr-debug, Dumping out compiler intermediate structures
-dppr-user-length, Dumping out compiler intermediate structures
-dshow-passes, Dumping out compiler intermediate structures
-dshow-rn-stats, Dumping out compiler intermediate structures
-dshow-unused-imports, Dumping out compiler intermediate structures
-dstg-lint, Checking for consistency
-dverbose-core2core, Dumping out compiler intermediate structures
-dverbose-stg2stg, Dumping out compiler intermediate structures
-dynamic, Options affecting linking
-E, Modes of operation, Batch compiler mode
-E option, Batch compiler mode
-f, Package management (the ghc-pkg command)
RTS option, Running a compiled program
-F, Options affecting a Haskell pre-processor
RTS option, RTS options to control the garbage collector
-f* options (GHC), -f*: platform-independent flags
-fasm, Options affecting code generation
-fbyte-code, Options affecting code generation
-fcontext-stack, Language options
-ferror-spans, Help and verbosity options
-fexcess-precision, -f*: platform-independent flags
-fext-core, Generating and compiling External Core Files
-fffi, Foreign function interface (FFI)
-fforce-recomp, The recompilation checker
-fglasgow-exts, Language options, Foreign function interface (FFI)
-fignore-asserts, -f*: platform-independent flags, Assertions
-fignore-interface-pragmas, -f*: platform-independent flags
-finline-phase, Language options
-fno-* options (GHC), -f*: platform-independent flags
-fno-code, Options affecting code generation
-fno-cse, -f*: platform-independent flags
-fno-embed-manifest, Options affecting linking
-fno-force-recomp, The recompilation checker
-fno-full-laziness, -f*: platform-independent flags
-fno-gen-manifest, Options affecting linking
-fno-implicit-prelude option, When the compiler “does the wrong thing”
-fno-print-bind-result, Using do-notation at the prompt
-fno-state-hack, -f*: platform-independent flags
-fno-strictness, -f*: platform-independent flags
-fobject-code, Options affecting code generation
-fomit-interface-pragmas, -f*: platform-independent flags
-fPIC, Options affecting code generation
-fprint-bind-result, Using do-notation at the prompt
-framework, Options affecting linking
-framework-path, Options affecting linking
-funbox-strict-fields, -f*: platform-independent flags
-funfolding-creation-threshold, -f*: platform-independent flags
-funfolding-update-in-place, -f*: platform-independent flags
-funfolding-use-threshold, -f*: platform-independent flags
-funfolding-use-threshold0 option, Smaller: producing a program that is smaller
-fvia-C, Options affecting code generation
-fwarn-deprecations, Warnings and sanity-checking
-fwarn-dodgy-imports, Warnings and sanity-checking
-fwarn-duplicate-exports, Warnings and sanity-checking
-fwarn-hi-shadowing, Warnings and sanity-checking
-fwarn-implicit-prelude, Warnings and sanity-checking
-fwarn-incomplete-patterns, Warnings and sanity-checking
-fwarn-incomplete-record-updates, Warnings and sanity-checking
-fwarn-missing-fields, Warnings and sanity-checking
-fwarn-missing-methods, Warnings and sanity-checking
-fwarn-missing-signatures, Warnings and sanity-checking
-fwarn-missing-signatures option, Faster: producing a program that runs quicker
-fwarn-monomorphism-restriction, Warnings and sanity-checking
-fwarn-name-shadowing, Warnings and sanity-checking
-fwarn-orphans, Warnings and sanity-checking
-fwarn-overlapping-patterns, Warnings and sanity-checking
-fwarn-simple-patterns, Warnings and sanity-checking
-fwarn-tabs, Warnings and sanity-checking
-fwarn-type-defaults, Warnings and sanity-checking
-fwarn-unused-binds, Warnings and sanity-checking
-fwarn-unused-imports, Warnings and sanity-checking
-fwarn-unused-matches, Warnings and sanity-checking
-G
RTS option, RTS options to control the garbage collector
-G RTS option, Thriftier: producing a program that gobbles less heap space
-H, Help and verbosity options, Sooner: producing a program more quickly
RTS option, RTS options to control the garbage collector
-h<break-down>, hp2ps––heap profile to PostScript
-hb
RTS option, RTS options for heap profiling
-hc
RTS option, RTS options for heap profiling
-hC
RTS option, RTS options for heap profiling
-hcsuf, Redirecting the compilation output(s)
-hd
RTS option, RTS options for heap profiling
-hi-diffs option, When your program “does the wrong thing”
-hide-package, Using Packages
-hidir, Redirecting the compilation output(s)
-hisuf, Redirecting the compilation output(s)
-hm
RTS option, RTS options for heap profiling
-hr
RTS option, RTS options for heap profiling
-hy
RTS option, RTS options for heap profiling
-I, Options affecting the C pre-processor
RTS option, RTS options to control the garbage collector
-i, RTS options for heap profiling
-idirs , The search path
-ignore-dot-ghci, The .ghci file
-ignore-package, Using Packages
-ignore-scc, Compiler options for profiling
-k
RTS option, RTS options to control the garbage collector
-K
RTS option, RTS options to control the garbage collector
-keep-hc-file, Keeping Intermediate Files
-keep-hc-files, Keeping Intermediate Files
-keep-raw-s-file, Keeping Intermediate Files
-keep-raw-s-files, Keeping Intermediate Files
-keep-s-file, Keeping Intermediate Files
-keep-s-files, Keeping Intermediate Files
-keep-tmp-files, Keeping Intermediate Files
-l, Options affecting linking
-L, Options affecting linking
RTS option, RTS options for heap profiling
-m
RTS option, RTS options to control the garbage collector
-M
RTS option, RTS options to control the garbage collector
-m* options, Platform-specific Flags
-M<size> RTS option, Faster: producing a program that runs quicker
-main-is, Options affecting linking
-monly-N-regs option (iX86 only), Platform-specific Flags
-n, Help and verbosity options
-no-hs-main, Options affecting linking, Using your own main()
-no-user-package-conf, Package Databases
-Nx
RTS option, Options to enable SMP parallelism
-O, FAQ and Things To Watch Out For, Assertions
-o, Redirecting the compilation output(s)
-O option, -O*: convenient “packages” of optimisation flags.
-O* not specified, -O*: convenient “packages” of optimisation flags.
-O0, -O*: convenient “packages” of optimisation flags.
-O1 option, -O*: convenient “packages” of optimisation flags.
-O2 option, -O*: convenient “packages” of optimisation flags.
-odir, Redirecting the compilation output(s)
-Ofile <file> option, -O*: convenient “packages” of optimisation flags.
-ohi, Redirecting the compilation output(s)
-opta, Forcing options to a particular phase
-optc, Forcing options to a particular phase
-optdep, Forcing options to a particular phase
-optdll, Forcing options to a particular phase
-optF, Forcing options to a particular phase
-optL, Forcing options to a particular phase
-optl, Forcing options to a particular phase
-optm, Forcing options to a particular phase
-optP, Forcing options to a particular phase
-optwindres, Forcing options to a particular phase
-osuf, Redirecting the compilation output(s), Using Template Haskell with Profiling
-p, Time and allocation profiling
RTS option, Profiling
-P, Cost centres and cost-centre stacks, Time and allocation profiling
-package, Using Packages , Options affecting linking
-package-conf, Package Databases, Package management (the ghc-pkg command)
-package-name, Using Packages
-pgma, Replacing the program for one or more phases, Replacing phases
-pgmc, Replacing the program for one or more phases, Replacing phases
-pgmdll, Replacing the program for one or more phases, Replacing phases
-pgmF, Replacing the program for one or more phases, Replacing phases
-pgmL, Replacing the program for one or more phases, Replacing phases
-pgml, Replacing the program for one or more phases, Replacing phases
-pgmm, Replacing the program for one or more phases
-pgmP, Replacing the program for one or more phases, Replacing phases
-pgms, Replacing the program for one or more phases
-pgmwindres, Replacing the program for one or more phases
-prof, Profiling, Compiler options for profiling, Using Template Haskell with Profiling
-r
RTS option, RTS options for hackers, debuggers, and over-interested souls
-r RTS option, Using “ticky-ticky” profiling (for implementors)
-read-dot-ghci, The .ghci file
-Rghc-timing, Help and verbosity options
-RTS, Running a compiled program
-S, Modes of operation, Batch compiler mode
RTS option, RTS options to control the garbage collector
-s
RTS option, RTS options to control the garbage collector
-S RTS option, Faster: producing a program that runs quicker
-split-objs, Options affecting linking
-Sstderr RTS option, Thriftier: producing a program that gobbles less heap space
-static, Options affecting linking
-stubdir, Redirecting the compilation output(s)
-t
RTS option, RTS options to control the garbage collector
-threaded, Options affecting linking
-ticky, RTS options for hackers, debuggers, and over-interested souls
-tmpdir, Redirecting temporary files
-tmpdir <dir> option, Redirecting temporary files
-U, Options affecting the C pre-processor
-unreg, Unregisterised compilation
-V, Modes of operation, Package management (the ghc-pkg command)
RTS option, Miscellaneous RTS options
-v, Help and verbosity options, Sooner: producing a program more quickly
-w, Warnings and sanity-checking
-W option, Warnings and sanity-checking
-Wall, Warnings and sanity-checking
-Werror, Warnings and sanity-checking
-Wwarn, Warnings and sanity-checking
-x, Overriding the default behaviour for a file
-XArrows, Language options
-xc
RTS option, RTS options for hackers, debuggers, and over-interested souls, Time and allocation profiling
-XExtendedDefaultRules, Language options
-XForeignFunctionInterface, Language options
-XGenerics, Language options
-XIncoherentInstances, Language options, Overlapping instances
-XMonoPatBinds, Monomorphic pattern bindings
-XNoImplicitPrelude option, Language options
-XNoMonomorphismRestriction, Switching off the dreaded Monomorphism Restriction
-XNoMonoPatBinds, Monomorphic pattern bindings
-XOverlappingInstances, Language options, Overlapping instances
-xt
RTS option, RTS options for heap profiling
-XTemplateHaskell, Syntax
-XUndecidableInstances, Language options, Undecidable instances
-Z
RTS option, RTS options for hackers, debuggers, and over-interested souls
.ghci
file, The .ghci file
.hc files, saving, Keeping Intermediate Files
.hi files, Output files
.o files, Output files
.s files, saving, Keeping Intermediate Files
:, GHCi commands
:!, GHCi commands
:?, GHCi commands
:abandon, GHCi commands
:add, GHCi commands
:back, GHCi commands
:break, GHCi commands
:browse, GHCi commands
:cd, GHCi commands
:cmd, GHCi commands
:continue, GHCi commands
:def, GHCi commands
:delete, GHCi commands
:edit, GHCi commands
:etags, GHCi commands
:force, GHCi commands
:forward, GHCi commands
:help, GHCi commands
:history, GHCi commands
:info, GHCi commands
:kind, GHCi commands
:load, Loading source files, GHCi commands
:main, GHCi commands
:module, GHCi commands
:print, GHCi commands
:quit, GHCi commands
:reload, Making changes and recompilation, GHCi commands
:set, GHCi commands, The :set command
:set args, GHCi commands
:set prog, GHCi commands
:show, GHCi commands
:show bindings, GHCi commands
:show breaks, GHCi commands
:show context, GHCi commands
:show languages, GHCi commands
:show modules, GHCi commands
:show packages, GHCi commands
:sprint, GHCi commands
:step, GHCi commands
:trace, GHCi commands
:type, GHCi commands
:undef, GHCi commands
:unset, GHCi commands
__CONCURRENT_HASKELL__, Options affecting the C pre-processor
__GLASGOW_HASKELL__, GHC version numbering policy, Options affecting the C pre-processor
__HASKELL1__, Options affecting the C pre-processor
__HASKELL98__, Options affecting the C pre-processor
__HASKELL__=98, Options affecting the C pre-processor
__PARALLEL_HASKELL__, Options affecting the C pre-processor
–shared, Creating a DLL
––--show-iface, Modes of operation
––auto-ghci-libs, Package management (the ghc-pkg command)
––force , Package management (the ghc-pkg command)
––global, Package management (the ghc-pkg command)
––help, Modes of operation, Package management (the ghc-pkg command)
––info, Modes of operation
––interactive, Invoking GHCi
––make, Modes of operation, Using ghc ––make
––numeric-version, Modes of operation
––print-libdir, Modes of operation
––supported-languages, Modes of operation
––user, Package management (the ghc-pkg command)
––version, Modes of operation, Package management (the ghc-pkg command)

B

Bang patterns, Bang patterns
binary installations, Installing GHC
binds, unused, Warnings and sanity-checking
bugs
reporting, Reporting bugs in GHC
bundles of binary stuff, GHC binary distributions

C

C calls, function headers, Using function headers
C compiler options, Options affecting the C compiler (if applicable)
C pre-processor options, Options affecting the C pre-processor
CAFs
in GHCi, GHCi options
category
package specification, InstalledPackageInfo: a package specification
cc-options
package specification, InstalledPackageInfo: a package specification
Char
size of, GHC's interpretation of undefined behaviour in Haskell 98
code coverage, Observing Code Coverage
command-line
arguments, Command-line arguments
compacting garbage collection, RTS options to control the garbage collector
compiled code
in GHCi, Loading compiled code
compiler problems, When the compiler “does the wrong thing”
compiling faster, Sooner: producing a program more quickly
Concurrent Haskell
using, Using Concurrent Haskell
configure, Installing
consistency checks, Checking for consistency
Constant Applicative Form (see CAFs)
constructor fields, strict, -f*: platform-independent flags
copyright
package specification, InstalledPackageInfo: a package specification
CORE pragma, CORE pragma
Core syntax, how to read, How to read Core syntax (from some -ddump flags)
core, annotation, CORE pragma
cost centres
automatically inserting, Compiler options for profiling
cost-centre profiling, Profiling
cpp, pre-processing with, Options affecting the C pre-processor
Creating a Win32 DLL, Creating a DLL
CTAGS for Haskell, Ctags and Etags for Haskell: hasktags

D

debugger
in GHCi, The GHCi Debugger
debugging options (for GHC), Debugging the compiler
defaulting mechanism, warning, Warnings and sanity-checking
dependencies in Makefiles, Dependency generation
dependency-generation mode, Modes of operation
depends
package specification, InstalledPackageInfo: a package specification
DEPRECATED, DEPRECATED pragma
deprecations, Warnings and sanity-checking
description
package specification, InstalledPackageInfo: a package specification
DLL-creation mode, Modes of operation
do-notation
in GHCi, Using do-notation at the prompt
dumping GHC intermediates, Dumping out compiler intermediate structures
duplicate exports, warning, Warnings and sanity-checking
dynamic
options, Setting GHC command-line options in GHCi, Static, Dynamic, and Mode options

E

encoding, Haskell source files
Environment variable
GHC_PACKAGE_PATH, The GHC_PACKAGE_PATH environment variable
environment variable
for setting RTS options, Setting global RTS options
eval mode, Modes of operation
export lists, duplicates, Warnings and sanity-checking
exposed
package specification, InstalledPackageInfo: a package specification
exposed-modules
package specification, InstalledPackageInfo: a package specification
extensions
options controlling, Language options
extensions, GHC, GHC Language Features
extra-libraries
package specification, InstalledPackageInfo: a package specification

H

haddock-html
package specification, InstalledPackageInfo: a package specification
haddock-interfaces
package specification, InstalledPackageInfo: a package specification
Happy, “Yacc for Haskell”: happy
happy parser generator, “Yacc for Haskell”: happy
Haskell 98 language vs GHC, Haskell 98 vs. Glasgow Haskell: language non-compliance
Haskell Program Coverage, Observing Code Coverage
hasktags, Ctags and Etags for Haskell: hasktags
heap profiles, hp2ps––heap profile to PostScript
heap size, factor, RTS options to control the garbage collector
heap size, maximum, RTS options to control the garbage collector
heap size, suggested, RTS options to control the garbage collector
heap space, using less, Thriftier: producing a program that gobbles less heap space
heap, minimum free, RTS options to control the garbage collector
help options, Help and verbosity options
hidden-modules
package specification, InstalledPackageInfo: a package specification
homepage
package specification, InstalledPackageInfo: a package specification
hooks
RTS, “Hooks” to change RTS behaviour
hp2ps, hp2ps––heap profile to PostScript
hp2ps program, hp2ps––heap profile to PostScript
hpc, Observing Code Coverage
hs-boot files, How to compile mutually recursive modules
hs-libraries
package specification, InstalledPackageInfo: a package specification
hsc2hs, Writing Haskell interfaces to C code: hsc2hs
hs_add_root, Using your own main()
Hugs, Using GHCi
hugs-options
package specification, InstalledPackageInfo: a package specification

I

idle GC, RTS options to control the garbage collector
implicit prelude, warning, Warnings and sanity-checking
import-dirs
package specification, InstalledPackageInfo: a package specification
importing, hi-boot files, How to compile mutually recursive modules
imports, unused, Warnings and sanity-checking
improvement, code, Optimisation (code improvement)
include-dirs
package specification, InstalledPackageInfo: a package specification
include-file options, Options affecting the C compiler (if applicable)
includes
package specification, InstalledPackageInfo: a package specification
incomplete patterns, warning, Warnings and sanity-checking
incomplete record updates, warning, Warnings and sanity-checking
INLINE, INLINE pragma
INLINE pragma, INLINE pragma
inlining, controlling, -f*: platform-independent flags
installation, of binaries, Installing GHC
installer detection, Options affecting linking
Int
size of, GHC's interpretation of undefined behaviour in Haskell 98
interactive (see GHCi)
interactive mode, Modes of operation
interface files, Output files
interface files, finding them, The search path
interface files, options, Other options related to interface files
intermediate code generation, Generating and compiling External Core Files
intermediate files, saving, Keeping Intermediate Files
intermediate passes, output, Dumping out compiler intermediate structures
interpreter (see GHCi)
invoking
GHCi, Invoking GHCi
it, The it variable

L

language
option, Language options
LANGUAGE
pragma, LANGUAGE pragma
language, GHC, GHC Language Features
Latin-1, Haskell source files
ld options, Options affecting linking
ld-options
package specification, InstalledPackageInfo: a package specification
lhs suffix, Meaningful file suffixes
libdir, Modes of operation
libraries
with GHCi, Extra libraries
library-dirs
package specification, InstalledPackageInfo: a package specification
license-file
package specification, InstalledPackageInfo: a package specification
LINE
pragma, LINE pragma
link, installed as ghc, Installing
linker options, Options affecting linking
linking Haskell libraries with foreign code, Options affecting linking
lint, Checking for consistency
list comprehensions
parallel, Parallel List Comprehensions

M

machine-specific options, Platform-specific Flags
mailing lists, Glasgow Haskell, Meta-information: Web sites, mailing lists, etc.
maintainer
package specification, InstalledPackageInfo: a package specification
make, Using make
make and recompilation, Filenames and separate compilation
make mode, Modes of operation
Makefile dependencies, Dependency generation
Makefiles
avoiding, Using ghc ––make
MallocFailHook, “Hooks” to change RTS behaviour
manifest, Options affecting linking
matches, unused, Warnings and sanity-checking
memory, using less heap, Thriftier: producing a program that gobbles less heap space
methods, missing, Warnings and sanity-checking
missing fields, warning, Warnings and sanity-checking
missing methods, warning, Warnings and sanity-checking
mode
options, Static, Dynamic, and Mode options
module system, recursion, How to compile mutually recursive modules
modules
and filenames, Modules vs. filenames
monomorphism restriction, warning, Warnings and sanity-checking
multicore, Options affecting linking
multiprocessor, Options affecting linking

N

name
package specification, InstalledPackageInfo: a package specification
native-code generator, Batch compiler mode
NOINLINE, NOINLINE pragma
NOTINLINE, NOINLINE pragma

P

package-url
package specification, InstalledPackageInfo: a package specification
packages, Packages
building, Building a package from Haskell source
management, Package management (the ghc-pkg command)
using, Using Packages
with GHCi, Packages
parallel list comprehensions, Parallel List Comprehensions
parallelism, Options affecting linking, Using SMP parallelism, Concurrent and Parallel Haskell
parser generator for Haskell, “Yacc for Haskell”: happy
Pattern guards (Glasgow extension), Pattern guards
patterns, incomplete, Warnings and sanity-checking
patterns, overlapping, Warnings and sanity-checking
phases, changing, Replacing the program for one or more phases
platform-specific options, Platform-specific Flags
postscript, from heap profiles, hp2ps––heap profile to PostScript
pragma, Pragmas
LANGUAGE, LANGUAGE pragma
LINE, LINE pragma
OPTIONS_GHC, OPTIONS_GHC pragma
pragma, CORE, CORE pragma
pragma, RULES, Rewrite rules
pragma, SPECIALIZE, SPECIALIZE pragma
pre-processing: cpp, Options affecting the C pre-processor
pre-processing: custom, Options affecting a Haskell pre-processor
Pre-processor options, Options affecting a Haskell pre-processor
problems, What to do when something goes wrong
problems running your program, When your program “does the wrong thing”
problems with the compiler, When the compiler “does the wrong thing”
profiling, Profiling
options, Compiler options for profiling
ticky ticky, RTS options for hackers, debuggers, and over-interested souls
with Template Haskell, Using Template Haskell with Profiling
profiling, ticky-ticky, Using “ticky-ticky” profiling (for implementors)
prompt
GHCi, Introduction to GHCi

U

Unboxed types (Glasgow extension), Unboxed types
unfolding, controlling, -f*: platform-independent flags
unicode, Haskell source files
UNPACK, UNPACK pragma
unregisterised compilation, Unregisterised compilation
unused binds, warning, Warnings and sanity-checking
unused imports, warning, Warnings and sanity-checking
unused matches, warning, Warnings and sanity-checking
using GHC, Using GHC
UTF-8, Haskell source files
utilities, Haskell, Other Haskell utility programs