# HG changeset patch
# User Simon Farnsworth
# Date 1476017464 25200
# Sun Oct 09 05:51:04 2016 -0700
# Node ID 2e2c959de0fe2c17bf6c5f47c01035a36f13c593
# Parent dbcef8918bbdd8a64d9f79a37bcfa284a26f3a39
templater: provide arithmetic operations on integers
The termwidth template keyword is of limited use without some way to ensure
that margins are respected.
Provide a full set of arithmetic operators (four basic operations plus the
mod function, defined to match Python's // for division), so that you can
create termwidth based layouts that match the user's terminal size
diff --git a/mercurial/help/templates.txt b/mercurial/help/templates.txt
--- a/mercurial/help/templates.txt
+++ b/mercurial/help/templates.txt
@@ -43,6 +43,12 @@
.. functionsmarker
+We provide a limited set of infix arithmetic operations on integers:
+ + for addition
+ - for subtraction
+ * for multiplication
+ / for floor division (division rounded to integer nearest -infinity)
+Division fulfils the law x = x / y + mod(x, y).
Also, for any expression that returns a list, there is a list operator::
expr % "{template}"
diff --git a/mercurial/templater.py b/mercurial/templater.py
--- a/mercurial/templater.py
+++ b/mercurial/templater.py
@@ -33,6 +33,10 @@
"|": (5, None, None, ("|", 5), None),
"%": (6, None, None, ("%", 6), None),
")": (0, None, None, None, None),
+"+": (3, None, None, ("+", 3), None),
+"-": (3, None, ("negate", 10), ("-", 3), None),
+"*": (4, None, None, ("*", 4), None),
+"/": (4, None, None, ("/", 4), None),
"integer": (0, "integer", None, None, None),
"symbol": (0, "symbol", None, None, None),
"string": (0, "string", None, None, None),
@@ -48,7 +52,7 @@
c = program[pos]
if c.isspace(): # skip inter-token whitespace
pass
-elif c in "(,)%|": # handle simple operators
+elif c in "(,)%|+-*/": # handle simple operators
yield (c, None, pos)
elif c in '"\'': # handle quoted templates
s = pos + 1
@@ -70,13 +74,8 @@
pos += 1
else:
raise error.ParseError(_("unterminated string"), s)
-elif c.isdigit() or c == '-':
+elif c.isdigit():
s = pos
-if c == '-': # simply take negate operator as part of integer
-pos += 1
-if pos >= end or not program[pos].isdigit():
-raise error.ParseError(_("integer literal without digits"), s)
-pos += 1
while pos < end:
d = program[pos]
if not d.isdigit():
@@ -420,6 +419,28 @@
# If so, return the expanded value.
yield i
+def buildnegate(exp, context):
+arg = compileexp(exp[1], context, exprmethods)
+return (runnegate, arg)
+
+def runnegate(context, mapping, data):
+data = evalinteger(context, mapping, data,
+_('negation needs an integer argument'))
+return -data
+
+def buildarithmetic(exp, context, func):
+left = compileexp(exp[1], context, exprmethods)
+right = compileexp(exp[2], context, exprmethods)
+return (runarithmetic, (func, left, right))
+
+def runarithmetic(context, mapping, data):
+func, left, right = data
+left = evalinteger(context, mapping, left,
+_('arithmetic only defined on integers'))
+right = evalinteger(context, mapping, right,
+_('arithmetic only defined on integers'))
+return func(left, right)
+
def buildfunc(exp, context):
n = getsymbol(exp[1])
args = [compileexp(x, context, exprmethods) for x in getlist(exp[2])]
@@ -713,6 +734,20 @@
tzoffset = util.makedate()[1]
return (date[0], tzoffset)
+@templatefunc('mod(a, b)')
+def mod(context, mapping, args):
+"""Calculate a mod b such that a / b + a mod b == a"""
+if not len(args) == 2:
+# i18n: "mod" is a keyword
+raise error.ParseError(_("mod expects two arguments"))
+
+left = evalinteger(context, mapping, args[0],
+_('arithmetic only defined on integers'))
+right = evalinteger(context, mapping, args[1],
+_('arithmetic only defined on integers'))
+
+return left % right
+
@templatefunc('revset(query[, formatargs...])')
def revset(context, mapping, args):
"""Execute a revision set query. See
@@ -906,6 +941,7 @@
# methods to interpret function arguments or inner expressions (e.g. {_(x)})
exprmethods = {
"integer": lambda e, c: (runinteger, e[1]),
+"negate": lambda e, c: (runinteger, e[1]),
"string": lambda e, c: (runstring, e[1]),
"symbol": lambda e, c: (runsymbol, e[1]),
"template": buildtemplate,
@@ -914,6 +950,11 @@
"|": buildfilter,
"%": buildmap,
"func": buildfunc,
+"+": lambda e, c: buildarithmetic(e, c, lambda a, b: a + b),
+"-": lambda e, c: buildarithmetic(e, c, lambda a, b: a - b),
+"negate"
