HsVar v -> pp_infixly v
_ -> pp_prefixly
where
- pp_e1 = pprParendExpr e1 -- Add parens to make precedence clear
- pp_e2 = pprParendExpr e2
+ pp_e1 = pprDebugParendExpr e1 -- In debug mode, add parens
+ pp_e2 = pprDebugParendExpr e2 -- to make precedence clear
pp_prefixly
= hang (ppr op) 2 (sep [pp_e1, pp_e2])
pp_infixly v
= sep [nest 2 pp_e1, pprInfix v, nest 2 pp_e2]
-ppr_expr (NegApp e _) = char '-' <+> pprParendExpr e
+ppr_expr (NegApp e _) = char '-' <+> pprDebugParendExpr e
ppr_expr (SectionL expr op)
= case unLoc op of
HsVar v -> pp_infixly v
_ -> pp_prefixly
where
- pp_expr = pprParendExpr expr
+ pp_expr = pprDebugParendExpr expr
pp_prefixly = hang (hsep [text " \\ x_ ->", ppr op])
4 (hsep [pp_expr, ptext SLIT("x_ )")])
HsVar v -> pp_infixly v
_ -> pp_prefixly
where
- pp_expr = pprParendExpr expr
+ pp_expr = pprDebugParendExpr expr
pp_prefixly = hang (hsep [text "( \\ x_ ->", ppr op, ptext SLIT("x_")])
4 ((<>) pp_expr rparen)
pa_brackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]")
\end{code}
-Parenthesize unless very simple:
+HsSyn records exactly where the user put parens, with HsPar.
+So generally speaking we print without adding any parens.
+However, some code is internally generated, and in some places
+parens are absolutely required; so for these places we use
+pprParendExpr (but don't print double parens of course).
+
+For operator applications we don't add parens, because the oprerator
+fixities should do the job, except in debug mode (-dppr-debug) so we
+can see the structure of the parse tree.
+
\begin{code}
+pprDebugParendExpr :: OutputableBndr id => LHsExpr id -> SDoc
+pprDebugParendExpr expr
+ = getPprStyle (\sty ->
+ if debugStyle sty then pprParendExpr expr
+ else pprLExpr expr)
+
pprParendExpr :: OutputableBndr id => LHsExpr id -> SDoc
pprParendExpr expr
= let